June 2009 | MasterTechnician Online 1

http://www.mbusa.com/mercedes/#/servPrtsGenuine/

Conte

nts

Feature Stories 16 Turbochargers Pt2:

The Rise of the Machinesby Greg McConigaLast time, we covered history, operating principles, and design fundamentals. Now, for failures, diagnostics, and replacement alternatives.

30 Trimming the ABS... of Mid-’90s Chrysler Minivansby Kerry JonssonThey’re getting to the age where their ABSs are starting to fail, andthe problems could be anywhere. Here’s a diagnostic approach that will save time and keep costs down.

42 Make Before Break - Measuring Parasitic Currentsby Wade NelsonThe rule of thumb is, “Anything under 30mA is acceptable, anything over 50mA indicates an excessive draw.”

52 Are You Ready for the Hybrid Highway? Part 2by Tom NashIn this second of two parts, we’ll delve into the components, the technologies, how to service hybrids, and where to find training programs and resources.

Cover Story62 What happened to

the 42V System?by Tom NashThe really big deal that never happened. What caused these proposed high voltage systems to fizzle out?


4 MasterTechnician Online | www.mastertechmag.com

Feature Stories 76 Another Mystery Solved:

Hocus Focusby John AnelloA shop called me in to investigate a 2002 Ford Focus with 2.0L that had poor power on a hard acceleration.

88 A/C Leak Sealer: A Controversial Last-Resort Fixby John HessBone of contention: Will A/C sealant save the day or destroy Western Civilization?

100 You Can Repair Runflat Tiresby Dave RussYou don’t need that old black magic to fix runflat tires.

112 Another Mystery Solved: Wheel of Fortuneby John AnelloThe Auto Tech on Wheels tells us how he used high-tech means to justify trans removal to find the real cause of a no-start

122 GM “U” Body Automatic Level Controlby Greg McConigaEven though this system is typically trouble-free, it’s on so many vehicles you need to know about it

Departments6 Closed Loop

By Bob Freudenberger Letters to the Editor

12 Editor’s Page: IMHOBy Bob Freudenberger Observation and Celebration

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(Editor’s Note: We could’ve filled

up this new section with praise

from readers on what a great job

Master Technician is doing. Our

mission, however, is to use all the

space we can to give you info that

will help you in your demanding

profession. So, we’ll concentrate

on useful comments and criticism.)

Go-no-go and low pedal

Dear Mr. Freudenberger,

I read your article on valve

adjustments (Jan., ’07 MT), and

you did a great job on covering

a wide range of vehicles and

problems. I am so glad there is

a new magazine out there for

the complex automotive world

we work in.

Please do not take this the

wrong way, but I was surprised

that you did not suggest the go-

no-go feeler gauge. I am sure you

are aware that even the greenest

of technicians can get the proper

clearances with a go-no-go

feeler gauge. If that technician is

looking for a 0.010 in. clearance,

all he/she needs to do is grab a

0.009/0.011 in. go-no-go feeler

gauge and adjust to a perfect 0.010

because the 0.009 part of the feeler

gauge will slide in between the

components being adjusted, but

the 0.011 feeler gauge cannot slide

in if the adjustment is 0.010. As

you also know, if you can slide a

0.010 feeler gauge between two

items the clearance is greater than

the feeler gauge.

I also enjoyed your article on the

low brake pedal problems. With the

increased heat conditions and traffic

conditions a brake system has to

go through each day it is extremely

important to completely inspect the

brake system before doing a brake

service, and flushing the fluid is an


You are right -- I certainly should’ve

mentioned go-no-go gauges. I

believe I bought my first set maybe

35 years ago, and I know they can

help anybody who hasn’t developed

the “feel” for this kind of work. But

I’ve been comfortable with my own

skills in this regard for so many years

that I simply never thought of it.

Maybe I’ll dig around in one of my

rollaways to see if I can find my old

set, and start using it again.

Just as you say, helping our comrades

avoid mistakes helps our whole

industry, and gives our profession a

better reputation with society at large.

We pledge to try as hard as we can

to “keep up the good work.” It’s

committed, responsible people like

you who make the incredible effort

involved worthwhile. By the way, I’d

thought working as a line tech was

about as difficult a job as there is, but

trying to put out the best magazine is

beyond anything I ever imagined. At

least it doesn’t beat up my old hands

so much. B.F.

excellent suggestion for all vehicles,

especially the ones that have ABS/

traction control systems.

Thank you for your articles

because even someone like me who

has been in the automotive field for

over 45 years needs to update his

knowledge and share with other

technicians to bring respect back to

this most important trade.

As you know, if you take twenty

mechanics they will all have

a different feel or outlook on

anything. I am not concerned

with the experienced mechanic

such as yourself. I am concerned

about our industry helping the

inexperienced, or the experienced

mechanic who will not admit he

does not know how to do the job

right the first time. Any steps we

can take as an industry to avoid

mistakes is important to us all.

Keep up the good work, my friend.

Sincerely,

Eugene Field


More Mode $06

Hey, when are you guys going to

get off the pot and give us more?

I want more.

I want more of Mode $06 -- every

person I talk to goes, “Huh, what

are you talking about?”

So please in your infinite wisdom

tell me where I can find Mode $06

info on Japanese and German cars.

Thank you.

Eric Radloff

Believe me, Eric, we tried to get

something out of both M-B and

BMW on Mode $06, but neither

seems to think it has any value except

in the engineering process. We have

especially close relationships with

those companies since we at CmA

produce technical magazines for

them. But our service training and

other tech contacts haven’t been able

to help us. We’ll keep after them.

As far as Asian vehicles are

concerned, we had a story on Toyota’s

use of this mode assigned to the

foremost expert we know of, but he

was unable to do it because of a job

change. We’re still investigating it on

our own (Honda, too) and will try to

produce an article for a future issue,

but we can’t say when. Magazine

publishing is just like any other

business: You’ve got to have the right

people available at the right time. B.F.

CVT Omissions

Bob,

A couple of comments, not meant

to be negative. The magazine is

excellent as usual, but the CVT

article [in the January issue of MT]

makes no mention at all of service

intervals, special oils, or anything

that an independent shop can do in

the form of service. My neighbor is

a Chrysler tech. He claims that a

quick lube added one qt. of Dex3 to

a CVT trans and it was toast in 50

miles. The warranty was void. The

quick lube had to pay for a trans at

Chrysler. I would have liked to have

seen some information like that in

the article, assuming it is true.

Closed Loop


Keep up the great work.

Phil Fournier

Phil’s Auto Service

Hemet, CA

A serious omission, indeed, Phil,

which just proves that we can’t think

of everything. That’s why we’re

encouraging all of our readers to

make the effort to tell us when we’ve

missed something. We want MT to

be as interactive as possible. B.F.

H2O

In re-reading your article

on antifreezes, I found a great

discrepancy about using tap water:

not enough coverage about it.

I have never seen a shop that

would take the time or money to

buy distilled water. That is to say

that I have not seen all shops. Most

shops do not take this time as they

find that it is too cumbersome to

do and takes up valuable space.

And they believe that the customer

will never figure it out.

I personally use unmixed and

distilled water in my own vehicles

as I have only older vehicles, the

newest being a ’96, and have had

to replace the radiators in all. I do

trust premix. I am like all other

mechanics, I HATE WORKING

ON MY OWN DAILY DRIVER.

It really needs to be explained to

these shops why it is bad and how

they can really gain customers if the

proper mix is done.

The other thing I would like to

know is if there is a litmus test for

antifreeze to check for clorinate/

flouride in the system.

Anonymous

We heartily agree that the subject

of the water that’s half of the coolant

mix is important. We’re planning a

feature on it in an upcoming issue.

We try to have a dozen tech articles

in each issue, many more than our

competing magazines have. Still, it’s

impossible to cover every possible

topic in every issue.


While we don’t know of a particular

litmus test for water, you can go to

your local Home Depot or Lowe’s

and get a kit for about 10 bucks that

will allow you to test for hardness,

chlorine, pH, alkalinity, iron, etc. B.F.

More on low brake pedal

Hi Bob,

First, I want to thank you

for making Master Technician

available. I own an independent

repair shop and have signed up

all four of my techs as I feel it is a

valuable resource for them and

want them to take advantage of it.

I am going to institute a standard

practice of having each of them

responsible for talking about an

article from MT each month at our

shop meetings.

Next, I wanted to add my two-

cents worth regarding the “Low

Pedal Lament” article. It was very

informative and should help many

techs with this common problem.

Another thing I commonly see

that causes a low pedal feeling, but

wasn’t mentioned, is brake pads

sticking or seized in their mounting

bracket. Subarus and Toyota trucks

are the most common ones I see. On

Toyota truck/SUV front calipers of

the rigidly mounted/multi piston

design, if the pads aren’t seized in

their brackets, then one or more

pistons are stuck, which are almost

impossible to detect unless the

caliper or pads are removed so

piston movement can be evaluated.

This is such a common problem that

when I’m on a road test unrelated

to the brakes, I can detect with a

high degree of success when this

condition is present. I’m not sure if

it is more of a regional thing with the

road salt used here in the northeast.

Visually inspecting the pads, rotors,

etc. all looks fine, but when braking

the pedal travels much farther

than normal. This is the result of

the additional hydraulic pressure

needed to move the pads enough to

provide adequate braking. When

Closed Loop

I drive one of these cars I see it

more as diminished braking power,

but the customer and techs often

interpret it as just a low pedal issue.

Nathan Walker

Recertified ASE Master Technician

& L1

Walker Automotive, Inc.

Wilmot, NH

Dear Nathan,

Your interesting comments just go

to prove what I’ve always said: This

is a regional business. I don’t see the

same things in Florida that you do in

N.H., esp. where undercar corrosion

is concerned.

Your points are so well taken that, if

you don’t mind, I’d like to run them in

a new “Closed Loop” section we have

planned. All we at Master Technician

want to do is help our readers get cars

fixed right the first time, and info like

this can sure help.

Thanks for taking the time to write.

-B.F.

Christopher M. Ayers, Jr.President/Publisher

[email protected]

Bob FreudenbergerEditor

[email protected]

John Anello • Steve CampbellPaul Cortes • Kerry JonssonPhil Fournier • Chip Keen

Greg McGoniga • Tony Molla Tom Nash • Henry Olsen

Matt Ragsdale • Dave RussContributing Editors

[email protected]

Christopher Ayers IIIArt Director, Project Mgr.

[email protected]

Joann TurnerCirculation Manager

[email protected]

Kyle AyersWeb Master

[email protected]

Editorial, Circulation, Advertising Sales and Business Office:

Master Technician Magazine598 Pine Point Drive / Akron, OH / 44333

P.330.666.9886 • F.330.666.8912

If you have a letter to the editor, a Tech Tip or story idea, click here: [email protected], or on this website at www.mastertechmag.com.

Master Technician is published by CmA Communications, LLC. The publisher and editors of this magazine accept no responsibility for statements made herein by advertisers or for the opinions expressed by authors of bylined articles or contributed text.

The online version of Master Technician magazine is free to qualified automotive repair shop owners, managers and technicians. All other content on www.mastertechmag.com is available on a subscription basis. Visit www.mastertechmag.com for subscription information.

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IMHOby Bob Freudenberger

Editor ’s Page

(In My Humble Opinion)

Back when Master Technician was

a print publication, a reader wrote us

this message:

In the March, ‘07 issue, Bob

Freudenberger mentioned an

upcoming article on tech salaries. I

loved working on customers’ cars in

auto repair shops, especially mom-

and-pop shops [but] they don’t want

to (or can’t afford to) pay a decent

salary, or benefits for a family, or

pension, or anything else. That is why

I now work for the city transit division.

I don’t like the work! But they supply

all the other aforementioned perks.

The only way to stay in the auto repair

business is to own your own business.

I am considering leaving the auto

repair business altogether because the

local union employer is hiring and

willing to pay almost DOUBLE the

average repair shop and supply all the

Payday

perks on top of that. YES, I do miss the

challenge and the feel of figuring out

the tough ones and the appreciation

of a loyal customer. But if you read

between the lines even the shops you

talk about in your articles don’t want

to pay a GOOD wage. That’s why

Ron Ananian doesn’t have “an extra

highly-trained technician available

to help around the shop” And a lot of

you guys are working more than one

job. Fixing cars is great, but living life

comfortably is the main reason we all

get out of bed in the morning.

Bill Hannigan

While the situation has changed

somewhat now with dealership

closings putting many techs on the

street, I think my response is still

worthy of consideration, to wit:

TRADE MULTIPLE PART NUMBERS FOR ONE.

© 2008 CRP Industries Inc. All rights reserved.

When you order a Pro Series Timing Kit from CRP Automotive, you’ll not only get a genuine ContiTech belt — you’ll also receive all the other parts needed to do a complete timing belt and water pump service, including a hydraulic damper when one is required. All in one box, with one SKU number.

Pro Series Timing Kits also come with a limited warranty identical to the original car manufacturer specified timing belt change interval. Just another reason to ask your Parts Supplier or a CRP representative for a complete list of applications today.

CONTITECH REIN AUTOMOTIVE PENTOSIN

For more information, visit www.proserieskit.com © 2009 CRP Industries Inc. All rights reserved.

Available through participating:

www.proserieskit.com

TRADE MULTIPLE PART NUMBERS FOR ONE.

© 2008 CRP Industries Inc. All rights reserved.

When you order a Pro Series Timing Kit from CRP Automotive, you’ll not only get a genuine ContiTech belt — you’ll also receive all the other parts needed to do a complete timing belt and water pump service, including a hydraulic damper when one is required. All in one box, with one SKU number.

Pro Series Timing Kits also come with a limited warranty identical to the original car manufacturer specified timing belt change interval. Just another reason to ask your Parts Supplier or a CRP representative for a complete list of applications today.

CONTITECH REIN AUTOMOTIVE PENTOSIN

For more information, visit www.proserieskit.com © 2009 CRP Industries Inc. All rights reserved.

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It’s obviously time for me to bite the bullet and at least start a discussion on this difficult subject, which seems to be taboo among polite people in this business. Sometimes you’ve just got to look the truth in the eye no matter how awkward or uncomfortable it is. And the truth is this: Most technicians aren’t paid nearly enough considering how much they have to know, how hard they have to work, and their investment in tools, not to mention their value to society at large. Even though most of us love the challenge and the satisfaction of this profession, many, many are leaving every day for greener, easier pastures.

One of my neighbors once said, “I think mechanics are some of the smartest people in the world.” I agree, but, as the old retort goes, “If you’re so smart, why ain’t you rich?”

While some people are simply swept along into a career path by life circumstances, most of us do make choices along the way. I, for one, could’ve made a lot more money over the years if I’d switched to being an ad salesman or publisher instead of remaining an automotive writer/editor/photographer and technician, but those pursuits aren’t where my

meager talents, or my interests, lie. I wanted satisfaction from my work. I’m thinking it’s the same with many techs. You could be doing something else that pays better, but you’re in love with fixing cars. Face it.

The last place I worked as a line tech was indeed a mom-and-pop, just as Mr. Hannigan mentioned, although very technically sophisticated and profitable. Four bays, four lifts, two full-time techs, plus the proprietor, who is a tech and a half with great marketing skills, and his wife, who took care of day-to-day business.

Well, everybody liked that friendly, family atmosphere, and customers became friends and grateful patrons who brought us pies, coffee cakes, cigars, wine, etc. Since there was plenty of lucrative business, everybody was well paid, too.

I’m excruciatingly well-aware that I was blessed, and that the money part isn’t always that good elsewhere. That shop is in a location that had been all farms and woods when I was young, but has become an upscale bedroom community -- we call it the “wealth belt.”

Editor ’s Page

So, we could charge enough so that

everybody made a good living. This

shop owner is so good he’d do well

anywhere, but there’s no doubt that this

“boom town” environment fostered

success. For example, I remember a

day when a young customer brought

in both his new Mercedes-Benz

roadster and his wife’s Hummer for

routine maintenance. That was maybe

a hundred and fifty thousand dollars

worth of vehicles that we were taking

on, probably for life, from just one

household. That’s certainly not the

norm across the country.

Bottom line: Independent shop

owner are going to have to learn to

charge enough to support the great

talent that keeps their businesses alive.

I’m sure I’m going to get a “shipload”

of e-mail messages and letters about

this column, and how I didn’t really

get into the problem, or suggest much

in the way of solutions. Fine. That’s

just what I want. Let’s see if we can

fire up this discussion out there in

the real world and make a difference.

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by Greg McConiga

Last time, we covered history, operating principles, and design fundamentals. Now, for failures, diagnostics, and replacement alternatives.


when the cylinder pressure and

temperature cause the last bit of

unburned fuel in the cylinder –

called “end gases” – to spontaneously

explode in uncontrolled combustion.

Normally, a flame front rolls or

proceeds through the air-fuel mixture

in a few thousandths of a second

– depending on air-fuel ratio and

cylinder design it varies between .001

and .004 seconds – but the explosion

of detonation occurs so quickly it’s

measured in microseconds – literally

thousands of times faster than a

normal combustion process.

Detonation exists in three phases:

Inaudible (can’t even hear it over

normal engine sounds), audible

(the BBs or marbles-in-a-can sound

we’re all familiar with), and hard

detonation, which sounds like a

really bad rod knock or someone

with a big ball-peen under the hood.

Trust me, you’ll know it if you hear it,

and you won’t hear it long before you

end up walking! In over thirty years

I’ve only seen it a couple of times in

a street vehicle, and in both cases it

was too late. Depending on severity,

detonation unseats rings, anneals

parts, turns valves inside-out, sets

Let’s start by putting detonation

into perspective: It’s the biggest

problem with the high cylinder

pressures that turbocharging can

produce. Charge air coolers, proper

compression ratios, proper turbo

sizing and waste gate settings, engine

temperature and fuel control, timing

rates, quality fuels and tight oil control

all help stave off these explosions.

Sub or supersonic

While we’re on the topic, detonation

is NOT and never has been colliding

flame fronts. Flame fronts do not

make noise when they hit. You can

collide flame fronts all day long

and never enter detonation. Ford

twin-plug 2.3 and Nissan Nap-Z

engines intentionally created two

flame fronts, as have innumerable

aircraft, racing and specialty engines.

Normal combustion proceeds at

subsonic speeds and spreads by

thermal conductivity. Detonation

is supersonic and spreads by

shock compression. Subsonic and

supersonic: propagated by heat,

propagated by shock; that’s the

difference. Detonation occurs


up violent ringing vibrations in the

assembly, breaks rings, cracks heads

and blocks, destroys head gaskets,

fractures piston tops and pounds the

tar out of the reciprocating assembly.

Diagnosing detonation is easy --

the damage is so pervasive it’s like

diagnosing a tornado. On a teardown,

the piston top will be clean and

appear almost sandblasted. The land

above the upper ring may be beaten

down and the top ring pinched. In a

lot of cases, the piston will be burned

down the side or have a hole burned

through the dome. The upper half of

the rod bearings and the lower half of

the mains will show signs of fretting

or damage. Piston pins may be stuck

or sticky, rods twisted or cracked

and crankshafts fractured. On spark

plugs, you’ll see clean, almost sand-

blasted appearing porcelain and

under magnification you’ll see tiny

blue-black balls of molten aluminum

stuck to the insulator. In loud high-

performance engines, you’ll feel it

before you hear it, and if it’s hard

detonation you can’t lift fast enough

to keep from tearing something

up. For causes, think lean (less

evaporative cooling during the gas

exchange cycle), insufficient octane

(the numerical measure of a fuel’s

ability to withstand detonation),

secondary ignition sources and over-

advanced timing (lights the mixture

early, and pressure builds while the

piston is still trying to rise in the bore),

too much compression or boost (or

any other cause of high cylinder

pressures), cam timing and profiles

(early or late intake closing affects

cylinder pressure) and overheating,

either generally or locally (heat is

pressure in a closed system.)

Brave new world

Growing population aside, there are

a lot of things looming on the horizon.

Like all old technologies that grew into

Turbochargers Part 2

If you spin it too fast, it comes apart! Now you know what a burst wheel failure looks like.

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modern applications, turbocharging

is evolving. The improved efficiencies

of variable nozzle turbines, wastegate

elimination and ball bearing center

housing rotating assemblies are just

the start. Compressor and turbine

wheel shapes are evolving, housing

designs with multiple flow paths are

on the market, and lighter titanium

wheels and machined-from-solid

parts are just entering the world of

automotive turbocharging (you’ll

recognize the titanium compressors

– they will have cast iron compressor

housings instead of alloy to meet burst

wheel containment requirements --

think a scattershield for 20 times the

rpm of an engine).

Even wheel-to-shaft attachment

methods are changing. The oldest

design bore is smooth, with no

threads in the wheel, retained on the

shaft by a nut.

The treaded bore is just that;

the wheel bore is threaded and screws

right onto the shaft. The latest wheels

are boreless; they are bored and

threaded part way through the wheel to

eliminate the stress risers that emanate

from a through-bored wheel face,

which is a good thing at 100,000 RPM.

Expect to see even more advances in

gas and air flow control, and more

improved oil control, better cooling,

and reduced turbo lag.

Diagnosis and repeat failure prevention

Given good fuel control and

normal exhaust temperatures,

clean, properly maintained and

undiluted engine oil, water-

cooled center housings, properly

maintained air filtration and just a

few precautions on the part of the

owner, a turbocharger will last the

New compressor and turbine wheels are not through-bored. On this “boreless” wheel, a partial bore-through is threaded, and the wheel threads directly onto the shaft.



life of the car. If these conditions

aren’t met, there will be a failure,

and if there is a failure there is very

often little left to rebuild, especially

in the event of foreign object damage

(FOD), or lack of lubrication, the

two most common turbo disasters.

This is one reason that more and

more rebuilding is moving to the

manufacturers. Shafts, housings,

wheels and bearings are often

completely destroyed, making field

rebuilding financially impractical.

Before grabbing a fistful of tools and

tearing something apart, stop, look

and listen. Most people know what

a turbo-equipped vehicle sounds

like. There’s that characteristic

turbo sound, sort of a low pitched

whistle that rises in pitch with engine

speed. Take the time to road test

the vehicle and see if you’re hearing

and feeling what you should be

hearing and feeling. You might just

uncover an exhaust or intake system

leak by listening, or you might hear

something whirring or screeching

that ought to be silent. Plus, if you

know what it did before you’ll know

that you fixed it when you do your

final quality control road test.

Oil-related failures are usually due

to some manufacturer’s incredibly

long recommended oil drain interval

(What the hell are they thinking? Let’s

see… $30 oil change , or $2,000 turbo?

Journal bearings are oil-fed plain bronze bearings.

The oil feed inlet is on the top, the oil feed outlet is on the flange it’s sitting on and one of the two water supply ports faces the camera. Water cooling the center section is what really made turbocharging practical on passenger cars and light trucks.


Brains not necessary, apparently),

or poor maintenance on the part of

the owner. Turbos handle and retain

a huge amount of heat, even after

shutdown. You must use the correct

oil type and viscosity. Many of these

engines specify synthetic oils, so pay

attention. After the oil change, never

rev the engine until oil pressure

builds. If you don’t get proper gauge

movement, or the engine low-pressure

oil light isn’t out in 15 seconds, shut

‘er down and investigate. Even at

idle speeds it only takes about thirty

seconds to damage the turbocharger

bearings. If you rev the engine right

after oil change, you might damage

the bearings instantly. Don’t do it! If

you get a lubrication-related turbo

failure and it’s a water-cooled unit

make sure the cooling supply in and

out is unrestricted and that the cooling

system is operating properly. It’s also a

good idea to replace the oil supply and

return lines at the same time since there

have been many instances of these lines

coking shut with heat. I’d advise any

customers with turbocharged cars to

allow 30 seconds of idle time prior to

each shutdown after a normal drive

cycle. I know it’s a pain, but those few

seconds will extend turbo life and save

It’s not uncommon to seize bearings and snap shafts. Look for discoloration and tiny “welded” spots any time you have one apart.


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them money. I’d also advise customers

that if they’ve been out “whuppin’ it

up” to allow two or three minutes of

cool-down time prior to securing the

engine. It’s a small price to pay.

FOD

The second most common failure

is foreign object damage (or FOD.)

Make sure that during routine

service all shop towels, nuts, bolts

and wrenches are accounted for prior

to startup. Foreign objects may be

introduced by others, may fall off the

turbo itself – like the nut holding the

compressor wheel on the shaft – or in

the case of a severely restricted air filter

they may come from the inlet system.

A restricted air filter could collapse

and shred and become the source of

all kinds of debris in the intake tract,

and anything that touches either

wheel guarantees instant shrapnel.

There is no forgiveness if something

is ingested into a wheel spinning at

50,000-125,000 rpm. If you have a

FOD failure, you’ll need to clean the

inlet and charge air cooler to prevent

a repeat. If there’s any question about

whether the charge air cooler got

clean, replace it. On diesel engines,

remember that whatever you used to

clean the charge air cooler cannot be

combustible unless you’re willing to

risk a runaway engine.

Weakling?

Low-power concerns are often

assigned to the turbocharger

immediately, but that’s not always a

good idea. First of all, see if there’s a

lot of detonation sensor activity. On

late-model turbocharged vehicles,

not only will timing be retarded, but

boost may be shut off or limited. I’d

certainly put a pressure gauge on the

intake side, but don’t forget to look at

overheating, timing belt/cam timing

issues, restricted exhaust systems,

fuel pressure and volume and base

timing, if adjustable. Don’t step over

the obvious to get to the obscure.

Once the basics are covered, check

waste gate operation. I don’t have a

dedicated tester for waste gates, but I

do have a radiator pressure tester that

I’ve adapted to check the pressure at

which the waste gate starts to open.

If that’s good, and you’re still not

making boost, then you may find



yourself pulling the turbo off to

examine the wheels and shaft, which

is not always a pleasant job.

If you have to pull the turbo, now’s

the time to check for oil in the intake

manifold after the turbo, and the

exhaust system ahead of the turbine

and after. Even if you don’t have oil

consumption complaints, remember

that most people don’t check their

oil and that catalytic converters may

“eat” the oil smoke. Some turbos

use a mechanical oil seal, some use a

labyrinth seal and others rely on the

high shaft speed combined with dams

and diverters to sling the oil away

from the area where the shaft passes

through to the wheel. In most cases,

oil consumption will be the result

of shaft and bearing damage, which

should also show up as rub marks on

wheels and housings. If you find a

compressor or turbine wheel coked

or carboned up, it’s okay to clean

it, but never with any kind of metal

object, including a wire brush. The

slightest scoring on the wheel will

create a stress riser that will lead to

a burst wheel. Soft bristled brushes

and solvent only, please.

It doesn’t take a lot to trim off the ends of the blades. Even opening up the relationship between wheel and housing a few thousands will dramatically change the pump efficiency.

The gas/oil seal is a simple metal part resembling a piston ring.

Once removed, examine the

compressor wheel, turbine wheel

and their respective housings for

signs of damage or rubbing. Using

a bright light, take a careful look at

the compressor wheel. It should not

have a sandblasted or “softened edges”

appearance. If it does, it may have

been damaged by running without an


air filter. Turn the turbo by

hand. It should spin freely

with no scraping or rubbing.

Next, push in on one of the

wheels and turn it by hand.

Again, there should be no

rubbing. Finally, push in

on the other wheel and turn

it by hand and check for

rubbing. Any failure that

changes the shape of the

wheel or the contour bore

renders the turbo useless.

One last failure to mention: overboost. If there is a waste gate or VNT system failure, you could end up with more intake pressure than the engine was designed to handle. In many cases, overboost is the result of an overzealous owner bolting on power-up parts to gain that extra edge when he and his buddies are out drag racing their three-quarter ton pickups in the country (Hey! I’m a Hoosier, remember? I never said I was sophisticated!) Okay, here’s the story. I won’t say who was involved in this, but I have intimate knowledge of a certain middle-aged fellow who once owned a GMC Syclone turbocharged pickup truck.

Said middle-aged crazy individual expressed a need for more speed, and mysteriously an extra “tee” appeared in the wastegate line and said line was terminated with a carburetor jet as a calibrated air leak. Seems that the computer control system was smart enough to shut the fuel off in the event of gross overboost (and you haven’t experienced something lying down hard until you hit fuel shut-off on a turbocharged engine that’s building boost like an Atlas 5 launch vehicle – you’ll leave teeth marks in the steering wheel), but not smart enough to detect, say, 2.5-3.0 psi of extra intake pressure. After a good

It’s pretty obvious what we’re doing here. If you open the gate, the exhaust gases bypass the turbine wheel, slowing shaft speed.


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many fun Fridays nights laying waste to members of the local street-racing crowd, the truck appeared one day with a rather annoying ticking sound going on in the engine. On further investigation, it was determined that the noise was low, and seemed to be at crankshaft cadence. On teardown, we discovered that one connecting rod was twisted about 8-10 degrees, and shortened just enough for the

pin boss to hit the counterweight of the crankshaft as the piston swung through bottom dead center. Now THAT is cutting it pretty close! Moral of the story? If you get complaints of sudden violent shut down, or if you see overboost occurring during your diagnosis, remember there may be some other clown like that (moi?) out there trying to get that extra little

edge by modifying the boost map.

A non-removable backplate rebuilt Holset turbocharger.



locations; check the website below),

but Googling “remanufactured

turbocharger” brought up dozens of

potential suppliers. Depending on

the application and mileage, having

a good reman supplier could save

you and your customers a lot of

time and money. The majority of

remanufactured units out there are

probably going to have a new center

housing rotating assembly with used

compressor and turbine housings

around it, so service life should be

good. Keep it oiled, keep it cooled,

and keep debris out and you and

your customer will be happy.

Special thanks to Pat Kiel of Fort Wayne Diesel (part of Diesel

Injection Service Company - http://www.dieselusa.com/) for

several hours of help. Pat donated three boxes of parts and pieces,

new and used for my use over a weekend to get this story done.

I would also like to thank an extraordinarily professional group

of people at Garrett Turbo (http://www/turbobygarrett.com),

including Kyle Snyder and Craig Gibbs for sending us photos and

answering some very technical questions on short notice. Check out

their website for more technical information about turbocharging.

If these guys don’t know it, it isn’t worth knowing!

Finding replacments

Turbochargers aren’t really that

complicated. For the most part, they

are no longer field-serviceable, and

repairs are confined to replacement

AND making sure that the root cause

of failure is identified – nothing is

worse than calling your supplier with

a “defective part” only to find that the

swarf from the last failure clobbered

your new unit. In my case, I’d see

our friends at Fort Wayne Diesel

for remanufactured replacement

turbos (and they have other

http://www.dieselusa.com/

http://www/turbobygarrett.com/


To diagnose any system, you

need to understand how it

works. For this article, we’ll

assume you know the basic principles

of ABS so we can move right to

exploring the particulars of the Teves

Mark IV system and looking at some

of its common problems.

Trio

There are three major components

starting with the electronic control

module, which Chrysler refers to as

a CAB (Controller Anti-Lock Brake).

This monitors the wheel speed

sensors along with other inputs, and

controls the ABS hydraulic valve

unit, the next component. This

houses all of the isolation and decay

solenoids (four of each). Finally, we

have the ABS pump motors, which

create the hydraulic pressure needed

to reapply the brakes during an ABS

stop. There are two motors and two

accumulators, one set for each brake

circuit. The pumps don’t have their

own electrical connector and power

supply relay, but are connected to the


hydraulic valve unit and are serviced

together. Unlike other manufacturers,

the pump motor relay is mounted

in the power distribution center

and is not part of the motor or the

hydraulic valve unit. So, that pump

motor or relay circuit code does not

necessarily mean you have to replace

the whole ABS hydraulic assembly.

Brainpower

The ABS control unit is mounted

underneath the driver’s side of the

dash to the right of the brake pedal.

It gets power input directly from the

ignition switch. Once it sees that the

ignition is on, it grounds the ABS

main relay, which is mounted in the

junction block -- that is, the fuse box

underneath the dash on the left side

of the steering column. The relay

is in position #7. If you look at the

wiring diagram, you’ll see that once

This is the power distribution center. It houses the ABS pump motor relay, the light grey one in the middle of the box on the right. Since this relay is separate from the CAB and the hydraulic valve unit, we can test it for causing a pump motor failure message.

Here’s the ABS control unit or the CAB. You can remove the black connector cover and perform most of your electrical tests right here providing you can stand being wedged underneath the dash.


the relay is turned on the power from

fuse #17 in the power distribution

center is sent to pin #87A of the

relay and leaves by way of pin #30.

This supplies voltage to the ABS

hydraulic valves and back to the

power distribution center to power

up the control circuit of the ABS

pump relay. It also supplies voltage

to a separate pin on the CAB to verify

the relay is activated, and provides

voltage to the hydraulic valves as well

as to the Message Center. This voltage

to the Message Center prevents the

ABS warning light from being turned

on. If the relay is not energized, the

circuit remains grounded by the

main relay and the control unit

grounds the wire that turns on the

ASB light. A diode is wired into the

junction block to prevent the voltage

from the Message Center from being

grounded by the hydraulic valves or

the pump relay. We know it sounds

confusing in words, but if you read it

over with the wiring diagram in front

of you it does make sense.

Tr imming the ABS . . .

This is the junction block, which houses the ABS main relay (top row, second from the right, half hiding behind the diagnostic connector). You should hear this relay click when you turn the ignition key on.

In this diagram we have the wiring diagram for the ABS Main Relay. Use this diagram to follow along with the explanation of how it provides power to the Hydraulic Valve unit and controls the ABS light.

Click to enlarge.

http://www.mastertechmag.com/articles/2009/May/image/chryabswirediagL.jpg

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ABS relay and check for voltage at

terminal #86 of the ABS pump relay.

Now that we have our control unit

powered up, let’s review the inputs

it will use in an ABS stop. Of course,

there are the signals from the brake

switch and the wheel speed sensors.

The brake light switch input also

doubles as the brake light switch, so

unless you have a bad splice, a quick

stab at the brakes should let you

know if the switch is working. The

wheel speed sensors are AC pulse

generators, so if you scope them

you’ll see an AC waveform. Also, they

should have about 900 to 1300 ohms

of resistance.

So, we’ve talked about the CAB’s

power supply, but what about its

ground? That’s handled by two wires

found in the passenger side kick

panel, which are part of a ground

block with multiple wires.

How do I test it?

At least now we know that the main

relay not only powers up the system,

but controls the ABS light as well.

The fastest way to see if the relay is

working properly is to unplug the

Here’s the socket for the ABS pump relay. Pin #86 is the slot the farthest to the right, parallel to the right edge of the PDC. With the ignition key turned on, this pin should have battery voltage.

It’s difficult to get to the connector for the passenger side front wheel speed sensor and unplug it.



Watch out for cracked tone rings,

which may give you low speed

activation of the ABS for no reason.

Also, check if the vehicle has had

the axles replaced because he wrong

number of teeth on the replacement

will throw off the ABS.

If your scan tool is capable of

talking to the CAB module, you’re

in luck. You can monitor the wheel

speed sensors in data and see which

one is setting the code or not reading

properly. If the scope pattern looks

good and the resistance is within

specs, one problem often overlooked

is RFI. Check if any high-current wires

are running near the speed sensor

wiring. The sensors use twisted pair

wires to reduce interference, but high

current loads can still induce a code.

A problem that may come up is

“No Communication” with the CAB

module. Keep in mind the CAB is on

a CAN (Controller Area Network)

and any of the other control units

on the CAN may bring down

communications. First, try to talk to

other control units on the CAN and

see who’s talking back. Another way

to test the CAB through the CAN is to

unplug each control unit on the CAN

until you can start talking to the CAB.

You may find that when you unplug

the CAB you can talk to the other

control units. This would indicate a

bad CAB, or a loose power or ground

supply. One important item to know

is that the red brake warning light

does not have an input to the ABS

control unit, so the hydraulic portion

of the brake system will not turn on

the ABS light and visa versa.

Here’s the other side of the wheel speed sensor connector. The best way to get at it is to remove the 10mm bolt holding down the retaining bracket and pull the sensor through the hole. You’ll find you have much more room to work.


What about the hydraulic part?

What does the brain do with those

inputs? During an ABS stop, depending

on which wheel(s) is locking up, the

CAB module will ground any or all of

the four isolation and the four decay

solenoids to apply and reduce brake

pressure to the individual calipers.

As we said, the hydraulic unit also

houses the ABS pump motor and

accumulators, which make and store

hydraulic pressure for an ABS stop.

The hydraulic valves are supplied

voltage with the key on. To check

the solenoids and wiring, all you

have to do is check the eight pins at

the CAB for battery voltage. Keep in

mind that you must have the CAB

module plugged in -- otherwise, the

ABS main relay will not be energized.

The solenoids should have about 5

to 9 ohms each. The hydraulic valve

assembly is mounted under the van,

but you can check resistance without

putting the vehicle on a lift. Measure

between terminal #30 of the ABS

main relay and each of the eight pins

on the CAB.

If you just want to bleed the system

after a brake job, or for maintenance,

you can bleed them like conventional

brakes. Start off with the left rear

wheel followed by the right front, then

the right rear wheel followed by the

left front. If you’re replacing the ABS

hydraulic valve unit, however, you

will need a scan tool capable of the

“Bleed ABS” routine. This will activate

the solenoids while the brake pedal

is applied and purge the hydraulic

assembly of any air. For those of you

without this type of scan tool, you

The hydraulic valve unit and pump motor assembly is mounted underneath the vehicle, which makes R&R fairly easy. Notice the lettering stamped on the aluminum bracket outlining the four different brake circuits.


https://www.volvotechinfo.com/



can carefully drive the vehicle in

an empty area with no traffic and

perform some ABS stops. This will

cycle the air out of the system as the

ABS solenoids energize. However,

this is time-consuming -- you may

have to go out and drive it four or

five times and bleed it after each road

test. So, it’s not recommended, but it

may get you out of a pinch.

Under pressure!

Although the ABS pump motor

is part of the hydraulic assembly,

there are other parts to check before

replacing it. We mentioned earlier

that the ABS pump motor relay is

mounted in the Power Distribution

Center on the right side, the fifth

relay from the bottom of the box.

It gets voltage from maxi-fuse #7 in

the same box on terminal #30 of the

relay. This relay is only activated by

the CAB when the ignition is turned

on and during an ABS stop. You could

jump pins #30 and #87 and provide

power to the pump motor, but only

for a few seconds. These motors were

not designed to run for very long and

[8] testing like this may damage the

pump. The pump should draw 3.5 to

4.0 amps. Any more than that and it

may be on the way out.

You do have to make sure that you

have a good power supply to the pump.

If the voltage is too low, the amp draw

will read abnormally high and you

may believe the hydraulic assembly

needs to be replaced. The high pump

current draw will cause the ABS

(Below) You can monitor the amperage draw of the motor by jumping terminals #30 and #87. This unit settled down at about 3.8 amps.


This is a scope pattern of the voltage and current of the ABS pump motor. Notice that when Trace A goes up to approximately 12 volts, the amperage “inrush” peaks at over 40 amps (the current probe is set at 100mv/amp), but then settles down to about four amps, which is what we tested earlier.



light to come on. Unplug the pump

and activate the relay. You should

only see .1 of a volt drop from fuse

#7 to the power supply to the pump.

You can also leave the pump motor

plugged in and measure the voltage to

the pump while energizing the relay,

but, again, only for a few seconds.

One of the reasons we stress voltage

drop testing is that since the relay is

mounted in the Power Distribution

Center corrosion can build up in

the wiring under the PDC -- we’ve

seen copper oxide on the pins of the

relays where the wires connect. This

can lead to voltage drop and failure

of electrical components, including

the ABS pump motor. This is just

another problem to watch out for so

that expensive parts are not replaced

for no good reason. Ditto for the

ground side.

You have a code?

We mentioned using a scan-tool

to pull codes, but this is not entirely

true. Chrysler does not use numeric

trouble codes to identify the problem

in its self-diagnostic check. Instead, we

just get the description. Your best bet

is to match the scan tool’s description

with Chrysler’s description and

follow that flow-chart. Oh, we forgot:

Chrysler doesn’t call them flow-

charts. They’re diagnostic charts

or test charts or whatever else the

company wants to call them. The

chart numbers range from Test 1A

to 22A. Once again, match the scan

tool description with the test chart

description and you should be on the

right path to fixing this “code”.

Also, keep in mind that when a CAB

module gets replaced on later models

it must be programmed with info on

wheel and tires size, as well as engine

and transmission. Be prepared.

These vans are getting older, but we

still work on a lot of them. Keeping

the ABS system functioning, even on

a 10 year-old-vehicle, will keep your

customers coming back, whereas

the purchase of new minivan may

have them going to a dealer for a few

years. A fast and accurate diagnosis

will save you time and the customer

money, making the vehicle more

cost-effective to keep, and it’ll still be

a safe ride. What could be better?

With the increasing complexity of today’s automobiles... It pays to specialize.

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Determining the reason

a battery keeps going

dead includes testing for

parasitic draws. The rule of thumb is,

“Anything under 30mA is acceptable,

anything over 50mA indicates

an excessive draw.” The greatest

difficulties in measuring parasitic

draws are mostly practical matters.

Having a third hand would make

taking a parasitic draw measurement

much easier. Mistakes are easy to

make, like inadvertently opening a

car door, or leaving the keys in the

ignition. The first will blow the fuse in

your DMM, the second will give you

an incorrect reading. Here are some

tips and tools to make parasitic draw

testing faster, easier, and perhaps save

you a few meter fuses.

The primary difficulty in making a

parasitic draw measurement lies in

establishing the “shunt” connection

through your ammeter (DMM) prior

to disconnecting the terminal from

the battery post, without accidentally

breaking that shunt connection

The rule of thumb is, “Anything under

30mA is acceptable, anything over 50mA

indicates an excessive draw.”

Make Before Break --

Measuring Parasitic Currents

Make Before Break --

Measuring Parasitic Currents

by Wade Nelson


(Below) Nobody likes blowing DMM fuses.

while removing the terminal from

the battery post. It absolutely has to

be a “make-before-break” transfer to

avoid sending one or more modules

back into an initialization process.

Having a co-worker help you set

up the test leads on a parasitic draw

measurement is the fastest method

of getting the job done. Several

commercially available test adaptors

will allow you to accomplish the

task solo including the Kent Moore

J38568 and OTC 7645, or you can

home-brew an adaptor.

Commercially available parasitic draw test adaptor.


One eBay vendor, “A-fluke,” offers

a parasitic draw tester, similar to an

OTC7645, but with test leads already

attached. If you were to cut one

of the two leads, and insert a 10A

blade fuse holder or circuit breaker,

you’d have an almost perfect tool

for parasitic draw testing – one that

would prevent you from ever again

blowing an expensive meter fuse.

As with all measurements of

electrical current, you sever the

circuit, and insert your ammeter in-

line between the two severed ends.

But in this case, you can’t ever allow

the two ends to become completely

electrically disconnected. Current

must always be able to flow, either

through the battery cable itself, or

“shunted” through your DMM. If

the circuit gets completely opened

and you re-connect the leads, one or

modules in the vehicle will go into

an initialization routine, boosting

An inductive DMM eliminates connection problems, but simply can’t read as small a current as an ammeter in series.

Measuring Parasit ic Currents


current flow considerably. This may

or may not blow your meter fuse, but

it will definitely give you an incorrect

reading. You have to wait until that

process completes and they are ready

to go to sleep before you can try again.

On some vehicles, you can use a scan

tool to command modules to quickly

go to sleep, which is a time-saver

Calibration Run

You need to determine what

amperage range the parasitic draw

is in immediately after the ignition

is turned off, and approximately

how long it takes before the vehicle

goes to sleep. It could be 45 seconds,

or 15 minutes on different vehicles.

Baseline information from testing

similar vehicles can be invaluable,

and save you time on a “problem”

vehicle.

Suppose that for 30 seconds after

ignition off, you’ve got a current

draw of 2.2 amps, or 2200 milliamps.

After 45 seconds it goes down to

.12A, or 120mA. After five minutes

it then decreases to 17 milliamperes.

You may need to change the range

on your DMM, perhaps even which

jacks the probes are plugged into

to accommodate measuring such a

wide range of current levels. Since

changing the jacks, or even switching

the range, can momentarily break the

circuit, you may need to plan ahead,

and NOT insert your DMM into the

circuit until an appropriate time.

Pre-Test

GM’s parasitic draw test procedure

recommends road testing the

vehicle and activating ALL electrical

accessories, including the radio and

air conditioning prior to parking,

turning the ignition switch to the

OFF position and removing the key.

With today’s feature-laden cars, that

can be a lot of button pressing.

Be sure to unplug any accessories

from the cigarette lighter outlet and

any accessory outlets in the rear

of the vehicle. Most importantly,

remove the keys from the ignition.


Otherwise, some systems may stay

powered-up. Consider the effect on

the factory security system of having

the hood up. Look for hood switches,

and defeat them. Unhook any

underhood trouble lamps. If having

the hood up doesn’t prevent its use,

use the remote (key fob) to lock the

vehicle, just as you would if you were

leaving it in a parking lot. Make sure

all doors and hatches are shut.

Get Ready:

The most time-consuming

mistake you can make is starting the

measurement process with the fuse

in your meter already blown. Test it

beforehand by measuring the current

through an #1156 tail lamp bulb

set on one of the battery terminals,

using your meter leads to form the

other connection. It should read

approximately 1.6 amps. Have some

Get all your clips, clamps, etc. together before you start.


T o m o r r o w ’ s T e c h n o l o g y f o r T o d a y ’ s T e c h n i c i a n s

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extra meter fuses available in case

you screw up. Courtesy lamps alone

may not pull more than 10A, but

other onboard systems may “wake

up” if a door is inadvertently opened,

immediately putting the shunted

draw over your meter’s fuse limit.

Second, have all the alligator clips

and jumpers you could possibly

need, including perhaps some battery

charging clips or side post adapters,

so after getting everything hooked

up you can set your meter down and

walk away. Having to stand there and

firmly press a DMM probe into a lead

battery terminal gets very old after

very few minutes, especially the third

or fourth time you do it! This is where

a DMM with min/max recording

ability proves its value, since you can

walk away, and come back anywhere

from 10-30 minutes later and hit the

button to see the value.

Since you can’t simply pull a fuse for the alternator if you suspect it’s the cause of the draw, simply disconnect it.



Parasitic Measurement Gotchas:

The auto manufacturers seem to

be intent on making parasitic draw

measurements ever more difficult

to make. Here are some of the “land

mines” they’ve left behind:

•Reportedly, some Chryslers are

programmed to burn off the MAF

sensor wire in the middle of the

night, causing a noticeable increase

in current – several amps. A similar

report claims some Chryslers test 02

sensor heaters at oh-dark twenty.

•NVLD (Natural Vacuum Leak

Detection) can run on GMs for up to

45 minutes after Key Off.

•Toyota’s EVAP pump can run for

10-12 minutes starting five hours

after the engine is turned off.

•On Ford Escape hybrids, the antilock

brake system reportedly does a self-test

with the key off. But when?

•Boomerang 1 [theft recovery]

devices draw between 35 and 55 mA.

Boomerang 2 units “lay low” for 15

minutes when power is removed.

Details on LoJack current draws

aren’t available.

•Some GM regulated voltage control

(RVC) systems are designed to wake-

up, perform a task, and fall back to

sleep at regular intervals.

•OnStar will create draws for the

first 48 hours after turning the

ignition off. The system will cycle

every 10 minutes and spike to 250 mA

for about ten seconds, taper down to

75 mA for another 45 seconds and go

to less than 1 mA until the next cycle

begins. This cycle stops if power is

removed from the OnStar system for

a short period and will resume once

a GPS signal is reacquired.

•Some Chevy Dual Zone Automatic

A/C systems were designed to “stay

awake” for up to four hours after the

ignition is turned off.

•As always, check for TSBs.


The “Usual Suspects”

When a vehicle has an unacceptable

amount of parasitic current drain,

remove one fuse at a time until the

current drain falls to an acceptable

level. This will indicate which circuit

is causing the drain. If pulling a fuse

eliminates a parasitic draw, refer

to the vehicle’s power distribution

schematics to determine which

circuits are fed by this fuse. Careful –

you can’t just open the door to get to

an in-cabin fusebox!

Using 30mA as a baseline, you

can sometimes use the amount of

excessive parasitic draw to help

refine your guesses as to what may

be causing it. For example, is there

enough additional drain to suspect a

light bulb is illuminated somewhere?

Beware of non-fused circuits. A

failed diode on an alternator can cause

a parasitic draw that pulling fuses

won’t reveal. Some relay circuits may

Any non-O.E. add-on should be suspect, especially amps and alarm systems.



not be fused. Improperly installed

audio amplifiers staying powered up

all night long are some of the most

common causes of parasitic draws.

You’ll often see the power leads for

“suspect” systems “MacGuyvered”

directly to the battery terminals.

Before you pull a single fuse, unhook

these bad boys and re-check the

parasitic current levels.

Future of Parasitic Draw Testing

The future of parasitic draw testing

is either very dim or very bright,

depending on how you look at it.

The latest BMWs and Toyotas and

most hybrids incorporate a sensitive

battery current monitor directly

on the battery terminal. Combined

with the PCM, this is capable of

monitoring and recording parasitic

draws. All the tech need do is hook up

a scan tool and view recorded data.

Multiple battery setups can

complicate parasitic draw testing.

Hybrids aren’t the only vehicles

equipped with dual batteries these

days. Others vehicles include the

Mercedes McLaren SLR and Lexus

460, and “mild” hybrids like the

Chevrolet Silverado. Unlike large

trucks and RVs where two or more

12V batteries are simply connected

in parallel, various electronics

may greatly complicate parasitic

testing on these vehicles. Virtually

all hybrid “main” batteries

incorporate battery current

monitoring features, fortunately.

Summary:

Parasitic draws are one of the

three most common causes of

dead batteries. Any parasitic draw

over 50mA is suspect. With a little

practice making parasitic draw

measurements becomes secondhand.

The usual suspects in parasitic draw

measurements are aftermarket

stereos, amplifiers, and security

systems. Homebrew or aftermarket

adapters help make parasitic draw

tests easier. The key technique is

a “make-before-break” shunt of

battery current through the DMM

used to measure parasitic draws.


In the first part of this article,

we looked at the history and

development of gasoline engine/

electric motor hybrids, how they

function and which vehicles employ

hybrid drive systems.

In this second part, we’ll explore

hybrid technology, the service aspects

and where you can procure training

and resources for launching into

hybrid service and repair.

The basic message is that you

can service hybrids and need to

be knowledgeable about how they

operate, how to diagnose them, and

skilled in repair techniques – if you

want to be competitive.

Over a million gasoline hybrids are on the road and need service. Are you ready to handle the repair needs of this growing market? In this second of two parts, we’ll delve into the components, the technologies, how to service hybrids, and where to find training programs and resources. (Image Courtesy Cadillac.)


Components & technology

The components that set hybrids

apart from standard I.C. engine-

only vehicles are the high-voltage

generation, drive, control and storage

devices. Some of these components

range from 144-650 volts and should

be considered lethal. They are

indicated by bright orange wiring and

harness covers. Never attempt service

on these components unless you are

properly trained and experienced in

the technology. Always refer to the

specific service information for the

vehicle you are servicing.

In most cases, malfunctioning

or failed electric and electronic

components are simply removed

and replaced, with the exception of

some control modules, which can

be re-programmed.

Here are some generic descriptions

of these components found on

hybrid vehicles:

MotorsThe electric drive motors used in

hybrids are high-torque heavy-duty

permanent magnet motors. These

compact, but powerful, dynamos

operate on power raging up to

about 650 volts. Many also serve as

generators to create electrical current

to recharge the batteries or power the

vehicle directly.

Starter/GeneratorsThese dual-purpose motors are

referred to by vehicle manufacturers by different names. An Integrated Starter Alternator (ISA), or Integrated Starter Generator (ISG), is built, or integrated, into the existing hybrid structure, rather than hung on the engine as an accessory. The Flywheel Starter Alternator (FSA) found on GM pickups is an example.

Powerful motors, such as this one in the Honda Civic, drive the vehicle and generate current to recharge the battery pack. (courtesy Honda)


Are you ready for the Hybrid Highway?

What’s called a Belt Alternator Starter (BAS), however, is usually mounted on the engine like a standard belt-driven alternator. Presently, only GM uses BAS-type starter/generators. A good example is the Malibu Hybrid.

ConvertersConverters (DC-to-DC) alter

voltage up or down as needed for various components. This may require changing the battery voltage – which may range from 144V to 488V – to as low as 12V to power the lights, accessories and convenience systems, or step it up to as high as 650V to power drive motors.

InvertersInverters convert DC to AC for the

purpose of driving AC motors or other

devices, as well as to power 120V outlets

to run convenience items such as power

tools, or household appliances.

Regenerative braking technology

Regenerative braking allows a motor

to act as a generator when coasting or

braking. Kinetic energy that normally

would be wasted during braking is

converted into electrical energy to

recharge the battery.

DC-to-DC converters change the voltage level for various uses in a hybrid system. (courtesy Denso)

Inverters change DC current to AC flow for powering AC motors, or provide 120V AC current outlets. (courtesy Toyota)

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The energy conversion is not

achieved by producing waste heat in

the pads and rotors as in traditional

braking systems, but within the

integrated motor/generator units.

While the brake pads and rotors

stop the wheels at high speed

or in emergency situations, the

regenerative braking system slows

the vehicle in normal driving.

Regenerative braking takes place

when the foot is lifted from the

accelerator pedal, or the driver applies

the brake pedal. To visualize this effect,

think of the engine braking and drag

experienced when you downshift

with a manual transmission.

An important note on brake service:

Since the regular hydraulic service

brakes on hybrids get little use in

normal driving, especially around

town, the calipers and rotors can rust

to an extent that you’ve never seen

before. So, every time you’ve got

any hybrid on the lift, do a thorough

A monitor screen on this 2007 Toyota Camry Hybrid continually displays the hybrid operation and function, including the level of regenerated power (Courtesy Toyota).


brake inspection. Clean, lubricate,

or replace components that exhibit

advanced corrosion to keep you

customer safe

Electric A/C compressors

Electrically-driven air conditioning

compressors allow cabin cooling to

continue when the engine is stopped.

Also, they don’t rob the engine of

energy, as with conventional systems,

and therefore reduce fuel usage and

improve mileage.

BatteriesHybrid battery packs often have

their own dedicated control units,

monitoring systems and cooling

systems. All current (no pun

intended) hybrids use nickel metal

hydride (NiMH) battery packs.

These packs consist of many small,

D-size, 1.2-volt cells connected

together. The number of cells,

therefore, determines the total voltage

of the battery pack. For example, the

Toyota Prius combined 228 cells for

its 2001-2003 273.6-volt battery pack.

Electric-powered A/C compres-sors provide cabin cooling when the gasoline engine is not run-ning (courtesy Denso).

Hybrid high-voltage battery packs are usually located toward the rear of the vehicle for weight distribution, under the rear seat in this Lexus RX 400h (Courtesy Lexus).



Yes, you can fix hybrids

Right about now, you’re probably

wondering if you’ll be able to service a

hybrid when one rolls into your shop,

or if you’ll have to turn it away. The

answer is: Yes, you can service hybrids

– with some basic understanding and

common sense.

A hybrid vehicle, after all, is really just a car with a high-voltage battery, some sophisticated controls and one or more powerful electric motors. The rest of the vehicle consists of components and systems with which you’re already familiar.

Every hybrid has the same OBD II diagnostic system and data link connector found on non-hybrid

This underhood photo of a Honda Accord clearly shows the bright orange high-voltage system harness. NEVER probe this harness or the connectors (Courtesy Honda).


vehicles, so you can easily connect a scan tool and read codes.

Just as you would with any type of vehicle you’ve never serviced, take the time to read the owner’s manual, log onto your service information provider’s system, and/or visit the manufacturer’s technical information website to educate yourself about the vehicle before beginning work.

Better, you should gain some knowledge and a little practical experience working on hybrids if you plan to make them part of your business. Taking a class in hybrid service is strongly recommended for a full working knowledge of hybrids.

That being said, let’s cover some important factors you should keep in mind when servicing hybrids.

Safety first! No kidding

You’re going to be working around very high voltage. Always take proper precautions.

1. NEVER – under any circumstances – probe the bright orange high-voltage system harness or connectors.

2. ALWAYS shut the high-voltage system down when working anywhere near a hybrid system-related component. The shut-off switch can be located by reading the owner’s manual. It may be in the trunk, behind the rear seat, or elsewhere. Be sure to wait the appropriate 5-10 minutes after flipping the switch for the system’s capacitors to discharge. Refer to the correct service information for specific details.

3. BE SURE to remove the key from the ignition and make sure the vehicle is in park before working around the accelerator. On models that incorporate a proximity key system that doesn’t require the insertion of a key, only that the fob transmitter is within a certain range before the START button is pushed, make sure the fob is out of range. Examples include later models of Toyota or Lexus vehicles.

4. ALWAYS educate yourself about the intricacies of the specific vehicle you intend to service, just as you would any other vehicle. Access the correct service information from your service information provider, or log onto the manufacturer’s technical information website.



Manufacturer technical information websites

For basic maintenance and service information, you can access your regular service information provider, but most don’t include detailed information on hybrid components and specifications. The best sources for hybrid diagnostics, repair and parts information are the technical information websites of the vehicle manufacturers. Each, of course, requires a fee for use. These websites may be accessed through the National Automotive Service Task Force (NASTF) website at www.nastf.org, or individually as listed below:

Chrysler www.techauthority.com

Ford www.motorcraft.com

GM (Chevrolet, GMC, Saturn) www.gmtechinfo.com

Honda www.ServiceExpress.Honda.com

Mazda www.mazdatechinfo.comNissan www.nissantechinfo.com

Toyota www.techinfo.toyota.com

Hybrid system parts

Because there are no aftermarket sources yet, all new or remanufactured hybrid components must be purchased through OE dealers. The 2000 EPA mandate and the NASTF agreement ensure that every automobile manufacturer will make parts, tools and service information available to aftermarket service sources.

Special tools

Special tools for servicing hybrid components are also available under the NASTF ruling by visiting the OE websites listed above. In most cases, you do not have to log onto the website, thereby incurring a fee, to access the tool source information.

Hybrid training courses

Auto Career Development Center

(ACDC)Craig Van Batenburg’s popular

multi-day in-depth hybrid classes are available for technician groups on


http://www.nastf.org

http://www.techauthority.com

http://www.motorcraft.com

http://www.gmtechinfo.com

http://www.ServiceExpress.Honda.com

http://www.mazdatechinfo.com

http://www.nissantechinfo.com

http://www.techinfo.toyota.com


Even before 1900, vehicles powered by electric motors and gasoline engines were developed

and sold to the public. In 1898, carriage maker Jacob Lohner & Co in Vienna, Austria asked employee Ferdinand Porsche to create drive system that incorporated both electrical and gasoline engine propulsion.

Porsche’s series hybrid system fitted a motor to each of the front drive wheels. A gasoline engine powered a generator to power the motors. Porsche proved the system himself by driving prototype vehicles to several European speed records and won a few races. Over 300 of the Lohner-Porsche “hybrids” were sold to buyers from 1901 to 1906, before the competition from lower-priced gasoline-only vehicles eliminated them from the scene. Over the next few decades, other gasoline/electric vehicles entered the marketplace; only to meet the same fate (courtesy National Automotive History Archives).

request, or are regularly scheduled at various locations. He also has several books and manuals on the subject of servicing hybrids. Check the website or call for more information.

www.auto-careers.org 800-939-7909

CARQUESTThe CARQUEST Technical Institute occasionally offers classes in hybrid

maintenance, generic hybrid service and specialized Toyota THS and HSD system diagnosis. These are eight-hour sessions taught at various locations around the country. Check the website, or ask your local CARQUEST provider for specifics. www.carquest.com

The 1898 Lohner-Porsche is considered to be the first successful electric/gasoline hybrid

http://www.auto-careers.org

http://www.carquest.com


A few years ago, we were

told that all vehicles

produced worldwide

would be equipped with 36/42-volt

electrical systems by the end of this

decade. It isn’t going to happen –

not for a long time, at least. It may

eventually come to fruition, but a

lot more research, development

and industry cooperation will be

needed. The big question at this

juncture: Is it needed?

The really big deal that never happened. What caused

these proposed high voltage systems to fizzle out?

by Tom Nash

It all started in the mid-‘80s, when

automotive engineers – mostly in

Germany – were concerned about

the ability of electrical systems

to handle all the technically-

advanced components slated to

be included in automobiles of the

future. The addition of passenger

convenience, safety, infotainment

and communications systems, and

onboard interactive control and

regulating modules would require

big increases in electrical capacity.


More efficient, lightweight

electrically-driven, electronically-

actuated and controlled systems

(called mechatronics) were being

developed, including drive-by-wire

throttle, power steering, brakes,

suspension, electronically-controlled

electrically-powered valves, electric

cooling fans, coolant (water) and

oil pumps, to name a few. These

components and systems, some

already in use, provide better

dependability, suffer less wear and

serve to reduce weight, all the while

not stealing energy from the engine.

Addressing the on-board energy

crisis and achieving the efficiency,

packaging and mechatronics benefits

would be easy, according to the experts,

with elevated electrical architecture. It

all sounded ideal and relatively simple

for the industry to change to a higher

operating voltage with commensurate

amperage and wattage. While it

sounded good in theory, it didn’t quite

work out as expected. Many, many

factors led to the delay and possibly

long-term postponement of the

36/42-volt parade.

Big Drag

Another big consideration was

engine efficiency. The amount of

energy needed to drive auxiliary

systems – such as the AC compressor,

power steering pump, water pump,

etc. – drags down the efficiency of the

engine. It was foretold that the savings

in fuel realized by the changeover to

electrically-powered components

could run as high as 20%. As a result of

this reduction in fuel burned, we were

told, emissions would be lowered and

the environment would benefit.

Engine compartment packaging

was another justification. Just think,

you wouldn’t have to have all those

accessories hanging off the front

of the engine and being driven by a

bulky belt/pulley/tensioner system.

Instead, you could mount them pretty

much anywhere you wanted. This

could also be a boon to serviceability.

How about a water pump wide open

on the fender apron?


What’s a 36/42-Volt System?

First, let’s clarify what is meant by

36/42 volts. The present automotive

electrical architecture is actually 14

volts, as you know. We all refer to it as

a “12 volt” system because the battery

has six 2.1 volt cells for a total of 12.6

volts, which charges just right at 14

V. A more accurate name would

probably be the “12/14 volt” system.

Triple that and you’ve got 36/42.

When automotive engineers began

looking for a higher system voltage to

establish as a standard, they wanted

to raise the level as high as possible,

but not so high as to create a shock

danger to humans.

Mercedes-Benz is credited as

being the first automaker to call for

higher voltage systems. An industry-

wide research consortium was

formed, led by the Massachusetts

Institute of Technology. The MIT/

Industry Consortium on Advanced

Automotive Electrical/Electronic

Components and Systems began

to address the technical issues of

changing over to 36/42 volts. The

research was financed by automotive

companies, which ponied up $50k

each to be part of the consortium.

After establishing that human tissue

can be damaged at around 56-60

volts (wattage and amperage levels

being considered), and assuming

that present components could easily

be adapted, the architecture point of

36/42 volts was derived. It sounded

simple and eminently logical.

Cast of Thousands

The first entities to get on board

would be the planning, standards and

regulation associations, organizations

and societies. In Europe, automakers

and suppliers formed a working

group known as “Fourum Bordnetz”

to create standards for the Euro-

based International Organization of

Standardization (ISO).

On this side of the pond, the Society of

Automotive Engineers (SAE) became

the leader in gathering and sorting

out the various methods, devices

and knowledge for development

of standards. Working with the

top engineers from international

What Happened to the 42V System?


companies and organizations, SAE

began to call for technical papers and

form committees to set standards.

The foremost vehicle manufacturers

to become involved – because

they had the largest portions of

the global market and the biggest

technical budgets – were BMW,

DaimlerChrysler, GM, Fiat, Ford,

Honda, Peugeot /Citroen, Renault /

Nissan, Toyota, and VW/Audi.

BMW, GM, Ford and

DaimlerChrysler all boasted that

they would have 36/42-volt systems

on the road by 2003 or 2004. GM

showed its AUTOnomy fuel cell

concept equipped with a 36/42-volt

system and promised to produce

everyday drivers with similar

systems by 2007. Ford pledged to

have a hybrid Escape with 36/42

volts on the road in 2004 also.

At the turn of the century, GM showed off its futuristic AUTOnomy hydrogen fuel cell concept. The skateboard-like chassis contained the fuel cell, and all control systems were powered by 36/42-volt architecture. Production of the changeable-bodied vehicle was projected for 2008 (courtesy GM).


These companies began laying out

their plans for integrating 36/42-

volt systems and working with their

main component suppliers. Among

these highly-reputable suppliers

were Aisin, Bosch, Continental

Teves, Delco Remy America, Delphi,

Denso, Johnson Controls, Lear,

Magneti Marelli, Motorola, Valeo,

VDO Siemens, Visteon, Yazaki and a

host of others. They were drawn into

the creation of high-voltage systems

and began expensive research and

development initiatives. Many of

the products these suppliers created

for 36/42-volt systems still sit in

inventory, waiting for buyers.

Five years ago, Ford Motor Company was still planning on producing 36/42-volt vehicles within a few years. This is a cutaway view of the proposed 2004 Explorer AWD with a 42-volt Integrated Starter-Generator (ISG) and electrical system (courtesy Ford).



Implementation Imagination

The steps in implementation were

to have followed this pattern:

•The 36/42-volt architecture would

be initially applied to high-end

luxury vehicles where the cost would

readily be accepted. The technology

would then trickle down to entry-

level vehicles over a few years, once

the technologies were perfected and

made cost-effective.

•The European manufacturers –

primarily the German companies

– were slated to convert to the new

standards first.

Denso developed many components for 36/42-volt vehicles including (Left to Right) an integrated starter generator (ISG), a battery electronic control unit (ECU) and a DC-DC converter. (courtesy Denso)

integrated starter generator (ISG)

battery electronic control unit (ECU)

DC-DC converter

•Dual voltage systems were to be

used as an interim solution. Until

the design and production of 36-

volt components was perfected, 12-

volt sub-systems would be used to

power devices that have not been

redesigned for the higher voltage.

This could be achieved by the use of

two batteries – one 12-volt and one

36-volt – and coupling them with

a DC-to-DC converter, stepping

down the electrical pressure to

power those components still

functioning on 12 volts.

What Went Wrong?

There are many reasons why 36/42-

volt standards have not yet been

adopted and produced. The three


main culprits are technical difficulties,

corporate political posturing, and,

the big one, financial constraints.

Technically, many theories that sounded good in the laboratories and think tanks did not work out so well when it came to implementation and mass production. Some problems became bigger obstacles than first thought.

Progressing through all the international standard-setting meetings proved difficult because the many parties disagreed on technical details and began to champion ideas

that suited their own purposes. European, Asian and North American representatives all wanted to create standards based on their individual technical systems. This campaigning extended to companies that wanted the standards to reflect the use of products and components protected under their own patents. Of course, there’s nothing wrong with trying to protect your own corporate interests and ensure financial growth, but political maneuvering often gets in the way of true progress and bogs down the entire process.

One of the biggest factors in the waning efforts to develop 36/42-volt vehicles has been money. Each company involved has spent millions to design new components and systems, but those devices sit in limbo at this point. The return on investment hasn’t materialized, and may not. The general downward business trend in the automotive market forced companies to look long and hard at how they were spending money. To satisfy the need for profitability, most companies have now turned their R&D dollars toward other emerging technologies such as diesels, hybrids and fuel cells.

In anticipation of the planned 36/42-volt vehicle architecture, Robert Bosch created a 42 volt version of its popular alternator design with a peak power output of 4 kilowatts (courtesy Bosch).



Problems, Problems

Dr. David J. Perreault, a research

Scientist at MIT’s Laboratory for

Electromagnetic and Electronic

Systems initially led the MIT/

Industry Consortium on Advanced

Automotive Electrical/Electronic

Components and Systems. Dr.

Perreault presented a technical paper

and spoke at the Convergence 2000

conference on October 17, in Detroit.

He stated that the higher power

would allow many new systems to

be introduced and many existing

systems to work better.

“It doesn’t sound like it would be

that difficult to do,” Dr. Perreault

said. “But it turns out that there are

several subtle technical problems.”

This comment turned out to be

somewhat understated.

Some of these technical

difficulties were clearly explained

by Paul Nicastri of Ford Motor

Company’s Research Laboratory at

the 2001 International Automotive

Technician Network (iATN)

Convention in Dearborn, Michigan.

Nicastri exposed the problems with

electrical connections under a 36-volt

load. He stated that the entire system

will have to be redesigned to handle

the high voltage. Wires, relays, and

connectors will need improvements

to function without damage. Arcing

of 36-volt current is the primary

concern. Unlike 12-volt arcing,

which is fairly low in amperage, short

in arc length and easily disrupted, the

arc in a 36-volt system can be much

longer and reach extremely high

temperatures – over 4,000 deg. F –

posing a dangerous situation.

He demonstrated these arcing

problems with a video showing

normal and slow motion views of a

36-volt connector under load being

disconnected. The resulting arc and

flash entirely disintegrated the tip of

the male connector. The female end

was badly damaged and unusable.

Special arc-suppressing connectors,

he stated, would have to be developed,

and, most likely, the system will

necessarily need to be shut off before

servicing, using the types of switches

found on existing hybrid vehicles.


Nicastri also demonstrated the

increased corrosion factor of wires under

a 36-volt load, compared to 12-volts.

Enclosed, protected connections, he said,

will have to be devised.

18 Cells!

Batteries pose a number of problems.

High voltage batteries will need to

be durably encased for protection in

case of collision. The connectors will

have to be designed to cut the threat

of arcing. Special dual-stage relay-

controlled connections that shut off

power while the main contacts wed,

then reconnect have been proposed.

Delphi developed a prototype a few

years ago, but it was never produced

for the mass market.

The need to jump or charge 36 volt

batteries is another concern. Special

connections and devices will need to

be designed. The ability of a 36 volt

lead acid battery to safely withstand

even momentary reversal of polarity

has not been established. Mistakes

can happen, even with professionals.

Just imagine the possibilities with a

non-savvy vehicle owner.

The SAE began to address these obstacles in the late ‘90s by setting up standards committees. The Electrical Distribution Systems Standards Committee authored a standard known as J2622 - Battery Connections. Its purpose was to “define test methods and set standards for development, production, and field analysis of electrical terminals, connectors, and components that constitute the direct connection to the storage battery of road vehicles having 42 volt nominal electrical systems.” At last check, the committee had developed a model for a safe battery connection, but has not met in some time.

Another obstacle is the adaptation of lighting systems to the proposed 36/42 volt architecture. Preliminary testing indicated many problems with interior lighting, which would need to be stepped down to a lower voltage. Exterior lighting, especially headlamps, require further research to find cheap and efficient ways to utilize 36/42-volt energy. Without some basic redesign, headlamp filaments would have to be much longer and thinner, resulting in increased fragility and shorter burn life.


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One possible answer is adapting the

technology known as Pulse Width

Modulation (PWM). Used in other

areas for years (remember feedback

carbs?), PWM is simply a switching

on and off of the voltage, resulting

in a square wave form. With the

duty cycle cut in half, many of the

problems associated with arcing and

corrosion could be addressed. Much

research and engineering would,

however, be needed to develop PWM

devices suited to automobiles.

The SAE launched a program

to investigate the use of PWM in

late 1999. The SAE 42V Exterior

and Interior Lighting Cooperative

Research Program brought together

automakers and electrical suppliers

to discuss PWM adaptation, testing

and use on incandescent lamps.

These lighting problems are another

reason to advocate dual 12/14 and

36/42-volt systems within a vehicle.

Even the top automotive business

analysts were way off in their

predictions, prognostications and

projections. At the beginning of the

decade, Standard & Poor’s estimated

that car makers would build 46,000

vehicles with 36/36/42-volt electrical

systems in 2002. This number was

expected by S&P to increase to nearly

13 million by 2010. It isn’t going

to happen – at least not anywhere

near that quickly.

What’s Out There Now

There are vehicles operating with

36/42-volt systems on the road today.

General Motors began building and

selling light hybrid models of its full

sized Chevrolet Silverado and GMC

Sierra pickups with dual 36/42-volt

and 12/14-volt systems in 2004. The

sales numbers have been miniscule

and GM has used these trucks as a

sort of test fleet.

GM eliminated the conventional

starter and generator in favor

of a compact integrated starter/

alternator (ISA) located in the

transmission bell housing. This

flywheel/ISA/torque converter

creates up to 14,000 watts of

continuous power, which is stored



in a lead-acid battery pack for use

in starting the vehicle, powering the

electro-hydraulic power steering

system and providing 120-volt AC

power for plug-in outlets – two in

the cab and two near the rear of

the load bed.

A control module regulates the flow

of energy into and out of the starter

generator. It also converts the current

into different types for different

purposes: 42 volt DC is converted to

AC for starting, braking-regenerated

AC is converted to 42 volt DC for

recharging the glass mat battery

The integrated starter alternator (ISA) includes a rotor and stator, housed inside the transmission bell housing. It receives current from the storage battery pack to start the engine, then converts to a generator to create current, which is sent to the battery pack (courtesy GM).


pack, 14-volt power is converted to

42 volt for jump-starting, 42 volt is

converted to 14 volt for the alternator

function, and 42 volt DC is converted

to 120 volts AC for powering the

electrical outlets. Does this system

sound complicated enough for you?

Regardless, this complex technology

makes the two GM pickups ideal

for construction, agricultural and

industrial uses.

As of last October, Ford, MIT and

others were still working on “The

acceleration of the development of

new 42-volt high-voltage vehicle

electrical system standards through

the use of virtual engineering concepts

and global consensus.” Delphi and

many other deeply-involved supplier

companies have put 42-volt research

on the back burner, or are no longer

pursuing it at all.

The control module, shown here in the corner of the engine compartment, regulates the types and levels of electrical current used in the GM light hybrid system (courtesy GM).



As It Stands

Many requests for interviews and

information on the status of 36/42-

volt initiatives to tier one suppliers,

automakers and involved associations

in the preparation of this article

went unanswered or were tersely

dismissed. This leads one to believe

that the whole idea of converting to

36/42-volt architecture may have

been mistakenly undertaken. That

nobody in these organizations wishes

to openly discuss their conversion

efforts speaks loudly.

Perhaps it was premature. or the

perceived need caused a competitive

panic that resulted in depletion of

monetary and human resources.

Maybe the rapid advances in ultra-

high voltage hybrid technology have

leap-frogged the need for 36/42-volt

systems. It is to be hoped that the

annual global gathering of automotive

engineers at the SAE World Congress

in Detroit this month will shed new

light on the future of these systems.

We’ll let you know.

The integration of 36/42-volts – if

it ever comes – will impact the entire

industry from top to bottom, from

beginning to end, involving vehicle

manufacturers, tier one suppliers,

parts makers and service suppliers,

tool and equipment sources and the

aftermarket and independent service

facilities. It will be the most costly,

most time-consuming and most

radical event ever to happen in the

automotive industry. It would make

the switch to automatic transmission,

electronic ignition, or disc brakes

seem like a walk in the park.

The 12/14-volt architecture we’ve

used since the mid-‘50s continues to

evolve and still serves us well enough.

But, it does have limitations. Just as

6-volt systems needed to be raised

after almost half a century, perhaps

it’s time to move forward again, fifty

years later. The onus rests on those

who have the most to gain from

the change – the automakers. Once

they find it necessary, feasible and

cost-effective to make the change to

36/42 volts, we in the aftermarket

will have to follow with training and

lots of new tools and equipment if we

want to keep pace with the rapidly-

marching parade of technology.


A shop called me in to

investigate a 2002 Ford

Focus with 2.0L that had

poor power on a hard acceleration

(Figure 1). The vehicle, which only

had about 53,000 miles on it, idled

fine with no misfires or codes stored

in memory. It just didn’t have the

horsepower it should have had.

The shop had already replaced the

fuel filter and performed a back-

pressure check to rule out a clogged

catalytic convertor. The owner was

told by the garage that there was a

possibility that the fuel pump was

bad and it was suggested that he go

to the new car dealership to have it

changed under warranty. When the

Ford dealer’s tech checked the car,

he had a different opinion of what

was needed to fix the complaint. He

recommended a new transmission

because of the lack of torque and

a concurrent condition of engine

flare-up on acceleration. The torque

multiplication at the wheels just did

not seem to be adequate.

At this point, the customer called the

garage owner to let him know about

the outcome at the dealership, and the

garage owner recommended a local

transmission shop for a second opinion.

The trans shop proved the dealer

wrong, and now the vehicle was back

at the garage for further investigation.

This poor car was like a carnival ride

-- everybody wanted to take a turn in

the driver seat. There were too many

opinions and no solid answers.

Another Mystery Solved:

Hocus FocusT h e l i t t l e F o r d t h a t c o u l d n ’ t

by John Anello


too long to come out of first gear due

to the amount of throttle needed to

get the vehicle going. Holding the

throttle down farther created an

engine flare-up, which was followed

by a bang into second gear. It felt like

a bad transmission, but then again it

seemed like the engine did not have the

top-end torque it was designed to have.

At this point, I needed to run

some tests to determine if the

When I arrived at the shop, I drove

the vehicle to get a feel for the problem

the others had experienced. I warmed

the car up and it seemed to rev fine

with no hesitation problems. The

engine idled smoothly with no misfires

or apparent roughness. I placed the

transmission in drive and accelerated

normally from a dead stop, and it did

not seem bad at all. Then, I tried hard

acceleration. It seemed to accelerate

fine without holding back, but it took

Figure 1


engine was experiencing a fuel, air/

exhaust flow, or timing problem. I

started my diagnosis by checking

for codes in memory, and there

were none present (Figure 2). The

EVAP monitor had not run yet,

indicating that someone had erased

prior codes and stored freeze frame

information, but the vehicle did run

all the other monitors proving out

any fuel trim or misfire conditions.

When dealing with a low-power

condition, it is important to know that

most of the failures I have seen in the

field fall into the common categories

of lack of fuel, restricted air intake,

clogged exhaust, miscalculation of

volumetric efficiency, or an ignition/

valve timing issue. It was easy to just

watch data parameters on acceleration

to determine if the problem was fuel-

related, so I accelerated the engine

again from a dead stop at wide open

throttle while viewing some selected

PIDs (Figure 3). You can quickly see

that the PCM maintained fuel control

during the whole time indicating that

the power loss was not due to a fuel

problem. Had it been a lack of fuel, I

Figure 2

Hocus Focus

http://www.mastertechmag.com/articles/2009/May/image/hffigure2L.jpg


Figure 3

would have seen fuel trims maxed out

with an O2 sensor value constantly

below 500mV. Providing that the O2

is working properly, this quick test

eliminates the need to get too intrusive

by hooking up a fuel analyzer to check

fuel pressure and volume.

Now that I had eliminated the

possibility of a fuel delivery problem,

my next step was to perform a

volumetric efficiency test to check

air flow through the engine. After

all, the engine is nothing more than

an air pump and the PCM will use

the MAF calculation to determine

the proper fuel and ignition timing

mapping to keep the engine at peak

performance. The correct air flow

reading is dependant on the proper

calibration of the MAF, the amount

of restriction in the air inlet and

exhaust system, and valve train

integrity. To be accurate, this test has

to be done at wide open throttle while

driving. You also need to take into

consideration the ambient air temp,

altitude and engine size. This can

be done by recording your captured

scan data into a VE calculator, or by



simply plugging your engine and

ambient conditions into the Escan

VE program and letting it do all the

work for you while you concentrate

on your driving skills to maintain a

steady wide open throttle acceleration

to capture the data you need.

Once the proper information was

entered into the VE program, I put

the pedal to the metal from a dead

stop and captured the air flow data

(Figure 4). The actual volume of

air was 30% below the calculated

specification. There were no fuel

trim issues, which indicated that the

MAF was correct in its findings. The

exhaust back pressure had already

been checked by the garage and

found to be below three psi, and the

air inlet and air filter were checked

for restrictions and were okay. This

problem was valve train related.

I next hooked up my scope and

tagged the crank and cam sensors

to perform a correlation check by

viewing the signals in a superimposed

format (Figure 5) to prove my

suspicions. By pulling up a known-

Figure 4

Hocus Focus


http://www.castrol.com/castrol/iframe.do?categoryId=9021346&contentId=7038271


Hocus Focus

good pattern from my Ace Misfire

database (Figure 6), I could see that

the crank and cam correlation was off

by about 60 degrees. This is a quick

and easy check to validate mechanical

timing issues with trigger points,

but it alone still cannot prove out a

jumped timing chain or belt. There

have been too many situations where

I have found loose trigger wheels that

had lost their indexing, damaged

flywheels, worn crank pulley keyways,

or even sheared cam gear pins. The

only true way for me to quickly prove

out a valve train problem would be to

use a 300 psi pressure transducer in

a cylinder to get a true indication of

piston and valve correlation.

I removed the spark plug and placed

a spark tester on the wire. I next

screwed the pressure transducer and

adapter assembly into the cylinder

and started the engine to capture a

waveform. I shut down the engine and

zoomed in on the pressure pattern to

view the peak-to-peak pressure rises

indicating one combustion event

of 720 degrees. I placed the cursors

on the peak-to-peak compression

rises and then hit the Cam Timing

Figure 5



button within the EScope program

(Figure 7). The program automatically

placed five large purple cursors

creating four divisions of 180 degree

of crankshaft rotation and five smaller

purple cursors creating six subdivisions

of 30 degrees on the screen. You could

now see that the exhaust valve was

opening at about 75 degrees before

BDC of the power stroke (note that the

lowest fall after the compression rise is

where the exhaust valve begins to open).

Having seen many waveforms showing

exhaust valve openings between 30-

45 degrees before BDC of the power

stroke, this engine’s valve timing was

definitely off by 30 degrees or better.

It was now safe to instruct the garage

to pull apart the front timing cover,

which involved supporting the engine

with a jack, removing an upper engine

support and removing an upper metal

timing housing cover -- all that just to

expose the timing belt.

Once the timing belt cover was

removed, I marked the sprockets

with White Out (Figure 8). The cam

gear was off by about two teeth. Also,

the belt had some slop indicating that

Figure 6



Hocus Focus

the self-adjuster was not doing its job

of compensating for belt stretch. The

fix here was to sell the customer a

timing belt and a new belt tensionor.

I also recommended replacing the

water pump that ran off the belt as

a preventative maintenance measure.

Prior to being a mobile technician for

the last 15 years, I worked in an engine

rebuilding shop for five years and as a

dealer technician for another 10 years,

and I have seen so many guys in the

field skimp on so many types of jobs

to try to save a customer money by

not replacing a component that may

involve overlapping labor time. An

experienced tech should understand

that educating a customer is the best

way to sell needed work on a vehicle.

Doing this good deed will help to

prevent a return visit of the vehicle

on the hook. I find that whenever

you try to save a customer money

you always lose in the end.

It’s amazing to me how this Focus

timing belt went undetected by the

PCM, or even by a dealer tech who

knew Ford products well. On the other

hand, I can see this happening to any

Figure 7 * Details available at your authorized BMW center.©2008 BMW of North America, LLC. The BMW name, model names and logo are registered trademarks. All rights reserved.




Hocus Focus

tech because there were no obvious

signs that you would normally

associate with a jumped timing belt,

such as poor engine vacuum, rough

idle, engine misfire, dramatic loss

of power, erratic electronic spark

operation, or even popping through

the intake. This was a tricky Hocus

Focus that deceived everyone into

thinking that anything could be at

fault except the timing belt. Even

when I drove the car, I thought the

engine was all right and I was leaning

toward performing a transmission

stall speed test because it did seem

like a transmission problem.

I believe that the key to resolving

power issues is to keep it simple by

performing pinpoint tests to validate

engine performance, which can have

an effect on transmission performance.

Using “feels like” or failure pattern

tactics will only lead you down a dead

end street where you won’t find the

resolution to the initial problem. I

always strive to find new ways to fine-

tune my diagnostics to cut down on

labor-intensive intrusive tests and

component removal. As the technology

in equipment advances, it can only help

us to achieve new levels of diagnostic

strategies. I hope this story helps you

choose the right path when you hit that

diagnostic fork in the road.

Figure 8

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Typically, this is considered

suitable only for older cars

that aren’t valuable enough

to warrant the cost of an expensive

evaporator replacement. Our old

friend John, however, gives us the

rest of the story.

It’s that time of the year again. My

e-mail inbox is stuffed with pleas for

help in finding that magic retriever

of cold air -- a low-cost refrigerant

system sealer. It’s either that, or

they’re asking whether or not to use

one in the first place.

While sent in by folks of every stripe,

these requesters all seem have two

things in common: They’re cooking

in their vehicles and desperate for

relief, and their A/C systems won’t

hold a charge. Well, maybe they have

a third thing in common: They can’t

or won’t pay to have a professional

A/C shop fix the system properly.

Bone of contention: Will A/C sealant save the day or destroy Western Civilization? (courtesty Cliplight)

A/C Leak Sealer: A Controversial Last-Resort Fix

by John Hess


is leaking (has a crack) and

he thinks this might get

him thru the summer. Will

this damage the system in

anyway? Thanx in advance!”

Forget it -- a cracked compressor

and he’s worried about something

damaging the system?

Here’s another:

“I own a 1995 Plymouth

Voyager and I have been told

that I have a small leak in my

evaporator. What I would like

to know is if there is a way to

fix this without having to take

the dash off of my car. The air

conditioner is located behind

the dash. I have been given an

estimate of $500.00 to replace

the evaporator. I am basically

looking for some information

that would tell me if there

is something my husband

could do to fix it ourselves.

Any help you could give me

would be greatly appreciated.

Thank you, Jane”

The normal reasons given for not

having the shop fix it are:

1. They don’t have the money.

2. The vehicle isn’t worth the

cost of a righteous repair.

3. They only need it for

one more season.

Or, all three (Number 2 is especially

applicable in states like California

where older vehicles may not pass

their next smog check).

Here are examples of the messages

I get. While some are definite

candidates for a sealant, others

obviously aren’t:

”My buddy is thinking

about putting some air

conditioner stop leak on his

‘95 Grand Am. I have never

heard of this before and my

first impression is don’t do

it. I’ve always heard not

to get anything in the air

conditioning system. Has

anybody tried this stuff

before? The compressor itself


Wow, talk about a tough sale. Though

that price is couple of years old, it was

still quiet reasonable at the time. Most

evaporator replacement jobs then were

at least $1,000. But Jane still wouldn’t

go for it. As Tony Soprano would say,

“Whatareyougonnadoaboutit?” Since

most Chrysler and Jeep evaporators are

good candidates for sealing, how about

someone offering to take a shot at fixing

it with a professional leak sealer?

You can find more testimonials,

both pro and con at:

http://www.imcool.com/articles/aircondition/ac_sealants_p2.htm

Up front, I’m well aware of the

negative feelings (to say it nicely)

that most A/C shop owners and techs

have about sealers. I also hear from

the other side, however, brethren

of the above who are using sealers

quite successfully. Joe Fortunato

(Automotive Air & Specialty, Jupiter,

FL), for instance, a 39-year A/C tech

and 25-year shop owner, is not shy

about using the Cryo-Chem product.

He’s been installing it for several years

and gets a 98% success rate when

used on true candidate vehicles,

such as the Plymouth Voyager above.

Joe doesn’t offer a warranty on the

service, but if the sealing job doesn’t

hold, he will credit the cost toward a

full evaporator replacement service.

How A/C sealants entered the vehicle market

As additional support for the viability of Cryo-Chem and sealants in general, I offer snippets from a post to the bulletin board at www.aircondition.com by George H. Goble, better known a few years on the internet as “ghg.”

We got this shot of a clogged orifice tube from the field. A do-it-yourselfer didn’t follow the proper procedures and really loaded the system up with sealer.

A/C Leak Sealer



http://www.aircondition.com


Background: George is the

inventor of several R-12 alternative

refrigerants, one of which is GHG-X3

that he introduced in 1990. Later

classified by ASHRAE, it became

known as R-406A, and eventually by

the trade name “Autofrost.” Yes, it is a

“blend” refrigerant (more on blends

in a future MT article).

Here’s how George described his

first “fix” in 1982 of his 1978 Datsun

810’s leaking A/C system:

“At first, I ran small tubing

(1/8” copper), and put a

manifold and dry-eye in the

passenger compartment. And

drove around with a 30lb

cylinder of R12 in the back

seat…and when the system

got low, just opened up the

low side manifold valve and

put in another pound of 12

while I was driving! Hell,

a 30lb cyl of R12 was only

$30 back then and lasted all

summer! What ozone hole?

When fully charged, and hot,

it lost about 1 pound/week.”

George was ready for a leak sealer,

and lo and behold:

“I met up with JJ Packo around

that time. My home central A/C

(R22) had started leaking about

1-2 lb/month (4 years old)…

They had a SSR12 “kit”, that was

two cans of R12, one with some

“dry-pak” dissolved in the R12,

and the 2nd with some cryo-

silane (gaseous epoxy) dissolved

in the R12. Kit was about $100.”

Take one “Home” A/C system leak

sealer kit, try it in a leaky car, and voila!

“Instructions were to put

on a new dryer, and change

the orifice tube (this car had

an expansion valve). I didn’t

change the dryer, but did a

10 min. vacuum, charged

in the 1 lb can of dry-

pak (about 2% dry-pack

concentrate, rest is R12),

put in a can of R12 (now at

2/3 charge)... and ran car

for 1/2 hour to circulate the

dry-pak, which converts the

free moisture into silicone


A/C Leak Sealer

oil (so it doesn’t form acids

anymore, and in this case,

removes the moisture, so the

cryo-silane won’t activate).

Next, added the Cryo-silane

(about 3% cryo-silane

concentrate in 12oz of R12),

and now at full charge.

For a couple of days, I noticed the

cryo-silane “dead fish” odor when

starting up the A/C (evap leak). After

two days, odor was gone, voila, it

worked. It self-sealed the evap leak!

And it held. That car never leaked

again. And in 1990 it became

the “development” car for GHG

refrigerants: GHG-X1, X2 (HCs),

GHG-X3 (R-406A/Autofrost), and

GHG-HP. In 1993, the fuel pump

died (but the A/C still worked), so I

junked the car.”

Interested readers are encouraged

to read ghg’s entire post at:

http://www.aircondition.com/wwwboard/current/18951.html

For those needing more evidence

of George’s refrigeration bona fides,

he is a senior systems engineer

for the Engineering Computer

Network department at Purdue

University. Besides inventing,

patenting and developing several

substitutes for Freon, check out the

paper he and colleagues presented

at the Purdue 1992 International

Refrigeration Conference -- Energy

Efficiency and New Refrigerants:

http://www.autofrost.com/peoples/ghg/ghg-ternary.pdf.

For those of you techs who

believe you know everything there

is to know about R-12, R-134a, and

associated lubricants, I challenge

you to read this piece and not learn

something new.

If you’re still convinced that sealants aren’t a viable service for “legitimate” A/C shops, I ask you, would a man who understands more about refrigerant systems—including vehicular—than most of us could absorb in a lifetime, flippantly suggest the usage of something that would damage them? Not hardly.



http://www.autofrost.com/peoples/ghg/ghg-ternary.pdf

http://www.autofrost.com/peoples/ghg/ghg-ternary.pdf

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soluTionRotate the compressor 2 turns using the Compressor Turner Tool, before attaching the drive belt to the compressor.

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© 2009 AutoZone, Inc. All Rights Reserved. AutoZone and AutoZone & Design are

SKU Description AvailableCOMPRESSOR TURNER TOOL204042 In Stock

ProBlemLubricant drains down during warehouse storage leaving an a/c compressor’s moving parts unprotected at initial startup.

feaTures>> Fits all compressors with a threaded opening in the clutch hub including R, H, and V series compressors

>> Uses a standard 19mm (3/4”) wrench

>> Won’t slip, and allows use of greater torque than a spanner wrench

soluTionRotate the compressor 2 turns using the Compressor Turner Tool, before attaching the drive belt to the compressor.

ComPressormanufaCTurers

ReCommeNDeD By

patent pending

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Do-it-yourselfers are the problem

So far, the sealant manufacturers

and parts houses have probably been

cheering this piece. Here, however,

is where we will probably part

company (I might even regain some

shop owner/technician supporters).

While it’s not illegal (where are the

environmentalists?), it certainly is

somewhat unethical, in my humble

opinion, to offer these products to

the DIY public. Why? For one thing,

because of the age-old human adage

that if one shot didn’t do it, give it

another [Editor’s note: How abour,

Too much is not enough?]. That’s

how systems truly do get fouled.

Then, if you need a certificate to buy

refrigerant and work on refrigeration

systems, why don’t you need a certificate

to buy refrigerant-sealing products

that circulate within the refrigerant?

I’ve not (yet) asked the manufacturers,

nor reps from the EPA, that question,

but someone really should.

Cliplight, a manufacturer of two A/C

sealants, Super Seal HVACR 944Kit

and the Super Seal Premium 946Kit,

has commented publicly on what DIY

sales of sealant products can bring:

“It should be appreciated

that the marketplace is full of

A/C leak sealers that are sold

directly to the DIY segment

and these products are injected

into an A/C system without

any measure of pre-inspection

of the system or control during

the injection process. It’s

also worth noting that these

products often contain:

· Hydrocarbon propellants

that will contaminate

a reclaim bottle.

· Dyes visible to the naked eye

without the use of a UV light

source that, under certain For some people, too much is not enough.

A/C Leak Sealer


conditions, can develop

crystalline formations in the

system and neutralize the

fluorescent dye intensity.”

Should the a/c system fail to respond

successfully to this DIY treatment, the

consumer -- in final desperation --

contacts a qualified service technician.

Most professional techs will refuse to

work on a vehicle that has had DIY

“cocktails” injected into the system.

If he does the first stage evacuation

process, it could present him with

nasty surprises! Especially if the

system had been contaminated with

moisture saturation (undetectable by

the DIY consumer).

Protecting the compressor

Understandably, most vehicle

manufacturers, along with A/C

component and recovery equipment

makers, are not proponents of A/C

sealers. As a rule of thumb, if they

find remnants of a sealer in anything

returned for warranty, the claim will

be denied. When a shop uses a sealer

in a system, either the shop or the

vehicle owner assumes responsibility

if contamination causes a problem.

Most technicians who use the product

will advise the customer that it is a

last ditch effort; there is no warranty.

Note: Cryo-Chem, SSR

International does offer dealers a

limited one-year warranty with its

SSR134Kit. It covers corrosion leaks

in condensers and evaporators. The

dealer must be 608/609 certified,

follow SSR’s installation directions

and satisfy other requirements.

Cliplight Manufacturing not only

offers a limited one-year warranty on

its product, but also, under “Coverage

B,” covers many A/C components. For

instance, if SUPER SEAL PREMIUM

was found (by Cliplight) to have

caused the failure of the compressor,

Cliplight will reimburse the dealer up

to $350. Since several conditions and

exclusions apply, be sure to check the

web page for the details:

http://cliplight.com/automotive/products.php?pageID=Warranty&productID=16&catID=4





Contamination protective devices

Recycle Guard from AirSept: To

protect your refrigerant recovery

equipment and clean jugs of

refrigerant, you do not want to

recover sealer-laden or otherwise

contaminated refrigerant. Airsept’s

Recycle Guard uses high-tech

filtration to separate and remove

sealant, dye, lubricant and solid

contaminants from the refrigerant.

These remain in the canister while

the vapor refrigerant exits to your

A/C machine (www.airsept.com/).

System Guard from

SYSTEMGUARD: To show if

someone has tampered with your A/C

service job (such as a vehicle owner

adding contaminated refrigerant or

DIY “stop leak,” then blaming you

for the disastrous results), slip either

a heat-shrinkable System Guard

sleeve or plastic tie wrap over each

service port. They’re color coded

and serial numbered. Once heat

shrunk or crimped to the port, any

disturbance will be clearly visible

(http://www.acsystemguard.com/).

(Above) This recycling machine solenoid is plugged with A/C system sealant. Not good.

(Left) Here’s the best way we know of to keep sealer and other contaminants out of your A/C machine (courtesy AirSept).

A/C Leak Sealer


http://www.acsystemguard.com/


Neutronics QuickDetect A/C

Sealant Detection Kit: QuickDetect

is designed to act as an A/C leak. If

sealant is present in the system, it

quickly solidifies in the disposable

test cartridge causing the flow meter

to show “no flow.” When attached

to the high-side port, if the flow

meter shows constant flow for two

to three minutes, it’s most likely

sealant free. If the flow rate visibly

decreases, the refrigerant contains a

sealant. Other than the low-cost test

cartridges, all of the QuickDetect

components are reusable

(http://www.refrigerantid.com/).

Whether you strap them on as shown, or heat-shrink the sleeve type, tamper-evident service port protectors will let you know if somebody’s been in there since you last worked on the vehicle (courtesy Systemguard).

http://www.refrigerantid.com/


John Hess, a Viet Nam vet, entered the radiator repair business in 1971. He is the editor and publisher of Cool Profit$ magazine

(www.imcool.com), a professional journal targeted to radiator and A/C technicians and shop owners, and the Heat Transfer Service Network (www.goHTSN.com).

This cleverly-conceived kit tells you whether or not there’s any sealant in the system so you can decide how to proceed (courtesy Neutronics).

For more information

about sealants, check out

the air conditioning pages of

www.imcool.com. Not only will

we offer a “Blog,” but also your

“Comments” can be added to our

articles that contain controversial

subject matter.

A/C Leak Sealer

http://www.imcool.com

http://www.goHTSN.com

http://www.imcool.com

Your reputation is in your hands.

As a supplier of original equipment hub units to most of the world’s automakers, SKF knows better than anyone what goes into making a premium quality hub unit.

So how can some manufacturers claim to offer OE quality hubs and sell them at half the price? The truth is, they can’t.

To prove it, we purchased a large sampling of these so-called OE quality hubs currently available in the aftermarket. We examined every component, and then tested each hub to every one of its actual OE performance specifications.

The results were clear: these hubs were not OE quality hubs. They were “value” grade hubs, which are no real value. Not only do they fail quickly, they can result in excessive NVH (noise, vibration and harshness), braking and handling problems, and expose drivers to potential safety risks.

Don’t compromise your customer’s vehicle safety. Always install SKF premium quality hubs!

See the results of our test at www.vsm.skf.com

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You don’t need that old black magic to fix runflat tires.

The idea of reinforced sidewalls seems simple enough, but what does it do to the ride, and how are you going to demount/mount such rigid tires (courtesy BMW).



Aaaaaaaaahhhh, runflat

tires . . . No more jack, no

more spare. No more air,

no more repair. And you can ride on

‘em forever, right?

Not quite. Most self-supporting-

type runflat tires -- for example,

Goodyear and Dunlop Extended

Mobility Tires (EMTs) -- are

essentially tires with ultra-stiff

sidewalls that don’t flex very

much when there’s little or no

air pressure, and thus can be run

“flat.” (DISCLAIMER TO TIRE

ENGINEERS: There’s a ton of

extremely sophisticated material

and construction engineering

involved, okay?)

Runflat tires can be driven at up to 50

miles per hour for 150 miles or so (your

mileage may vary; see owner’s manual

for details. . . .). The idea is to get you to

a repair facility in case of a flat.

Assuming you don’t exceed the

limits above and don’t shred the tire,

they can be repaired. CAUTION:

Some car manufacturers, BMW for

example, don’t recommend repairing

runflat tires, which makes for some

interesting conversation on BMW

owner blogs.

Beemer bloggers blast away

For example, “Louis,” Member

#2567, wrote in January that he was

considering leasing “a 2007 328i

sedan, which (like most or all new

BMWs) comes with runflat tires. Like

most people, I don’t like the idea of

runflat tires. I just can’t stop thinking

about the problems I will have to deal

with if one of the tires goes flat. What

I have heard is that one can drive 50

miles or so on the flat.”

by Dave Russ


To which “Doug” replied, “You

are not alone and as of right now

the whole run-flat tire scam should

be worrying everyone that enjoys

high performance automobiles.

But I will refrain from a full

ranting and hopefully we will see

some better answers along with

some unbiased commentary in

the BMW CCA Roundel magazine

soon. HINT! HINT!

“To answer your questions the

range is 150 miles driven gingerly.

No, they should not be and most of

the independent tire dealers I have

spoken with will not repair them. Yes,

by all means they can be replaced with

non-runflats on the same wheels.

Yes, they are expensive to replace if

they go bad and, no, your local tire

dealer is not likley (sic) to have them

in stock, although your BMW dealer

may, at tire prices only the devil

himself would charge. I have heard

rumors of $600+ each.

Demounting/mounting tires with such stiff sidewalls isn’t easy, but our friends at Hunter Engineering supplied this series of photos to show us how to do it without damaging the bead. First, get as much lube on the upper bead seat as possible so the bead can slide down into the drop center of the rim without too much force being applied.

You Can Repair Runflat Tires

MODEL SYSTEM I

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Americas Best Lift Investment...Because Quality Lasts A Lifetime

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(Above) With one side deeply into the drop center, you should be able to lever the opposite side over the lip of the rim.

(Below) For mounting, you start this bead depressor “tail” . . .



And another thing: “They ride horribly”

The blog continues: “That doesn’t

end the problems of runflats, either.

They also ride horribly on every

new BMW I have driven them on.

If I had a new BMW coming my

way soon I would bite the bullet

and either make the dealer install

comparable non run-flats as part of

the overall purchase or lease price...

Or buy them myself and install

them as soon as possible.

“The whole idea of the runflats

is to aid in eliminating the spare

tire for packaging purposes, etc.

That is perfectly fine with me as I

think they should be eliminated

also. But roadside assistance and a

. . . then insert these spacer blocks to keep the bead down in the drop center. If you tried to just force it, you’d tear the bead and perhaps damage your nice tire machine.


object, that object is likely to still

be in the tire and must be removed.

Additionally, if the tire is up and

running, a false sense of security

and forgetfulness could lead to non-

repair of the tire. Third, the goo from

the inflator makes quite a mess – not

much appreciated by the person who

ultimately repairs the tire.

decent inflator kit is a much better

solution than runflat tires unless

they improve drastically.”

Now that he mentioned it, tire

makers far and wide recommend

against using aerosol inflators to fix

flats. Why? While they may seal the

leak, if it was caused by a penetrating


The Michelin PAX system is another concept entirely. That inner ring supports the car, not stiff sidewalls, so ride quality isn’t affected. We wonder how you demount/mount without the extra space normally provided by an open drop center.

s i d e b a rs i d e b a r

INCORRECT OR IMPROPER

REPAIR WILL RESULT IN THE

TIRE NO LONGER BEING SPEED-

RATED BY GOODYEAR and the

warranty may also be affected.

READ ING : If a Goodyear,

Dunlop or Kelly-Springfield

manufactured speed-rated tire is

retreaded, it no longer is speed rated

by the company (and most runflat

tires are, by and large, speed-rated).

GOODYEAR PRODUCT SERVICE BULLETIN

Here are the Goodyear runflat repair

instructions verbatim, which are

applicable to other runflat tires, too;

however, not all runflat manufacturers

recommend repair and say you’ll void

the warranty if you do it.

SUBJECT: Puncture Repairing

and Retreading of tires that are “H”

Speed-Rated and higher (equal to

or greater than 130 mph) includes

Goodyear EMT & Dunlop DSST tires.

A Goodyear, Dunlop or Kelly-

Springfield manufactured speed-

rated tire may be repaired to correct

a commonly repairable nail hole

puncture in the tread area only, but

proper materials and procedures

must be applied.

Unlike some other manufacturers, Goodyear says its runflats can be repaired providing the proper procedures are used.

s i d e b a rs i d e b a r


The French way

There is another type of runflat tire, the Michelin PAX System, consisting of a conventional tire and an inner composite-type ring mated to the wheel. When the tire goes down, the weight is supported by the ring. As for repair, Michelin advises that the tire should be taken to an authorized Michelin PAX System repair outlet. Michelin has set up service centers around the United States, including all Honda dealers. A toll-free number finds the nearest one. Part of the PAX warranty is to replace any PAX wheel-tire system that has incurred air loss.

Goodyear says, “Like any other Goodyear speed-rated high performance tires, the Goodyear runflat EMT tire may be repaired to correct a nail hole puncture in the tread, but proper materials and procedures must be used.”

Goodyear supplies runflats for a number of OEM vehicles, including Corvette, Mini Cooper, Cadillac CTS-V, Rolls Royce, Lexus SC430, Maserati Quattroporte, Ferrari F360, Jeep Grand Cherokee SRT8 and several BMW and Mercedes models.

Goodyear’s attitude

“Some tire makers disallow puncture repairs on runflat tires,” says Goodyear spokesman Jim Davis. “However, punctures in our runflat tires can be repaired, according to the same guidelines as other tires. The servicing outlet needs to obtain information from the driver, and inspect the tire to make certain there are no signs of the tire being degraded due to being run at zero pressure for an extended period, much the same as an outlet would treat any other punctured tire. In any case, there is a product service bulletin on the proper repair of speed-rated tires, which includes EMTs” (see the sidebar).

If you want to bag it and send the customer to a Goodyear Run-Flat EMT service facility, or to get information on proper repairs, call 1-800-RUN-FLAT.

For other tires, be sure the repair doesn’t void the warranty, although even if it does, the customer may want you to go ahead and repair the tire so he or she can get back on the road.


DETAILED POLICY

Puncture Repair of Speed-Rated Tires

A. The puncture must be confined

to the tread area only.

B. Restrictions on the number and

size of repairs must be followed.

C. A detailed repair procedure must

be followed.

D. A speed-rated tire repaired in

strict accordance with items II-A,

B & C will retain its speed rating.

REPAIR PROCEDURE FOR SPEED-RATED TIRES

GENERAL

The objective of the puncture

repair is to seal the tire against loss

of inflation pressure and to prevent

damage to the carcass from moisture.

In all puncture repairs, approved

by Goodyear, Dunlop and Kelly-

Springfield, the hole must be filled

with a plug, and a patch covering

the hole must be applied according

to repair material manufacturer

instructions to the inside of the tire.

Never repair tires which are worn

below 2/32” tread depth.

NOTE: NO TIRE IS TO BE

REPAIRED WITHOUT FIRST BEING

REMOVED FROM THE RIM.

REPAIR AREA

Repairing is limited to the tread area

only within the outside grooves. No

repairs are allowed in the tread area

beyond the outside grooves or in the

sidewall area of the tire.

D. MATERIALS NEEDED

1. Precured rubber plugs - 1/4”

(6mm) diameter

2. Precured patches

3. Precured plug/patch combi-units

4. Chemical vulcanizing cement

5. Pre-buff cleaner

E. REPAIR PROCEDURE

1. Carefully remove the tire

completely from the rim.


2. Locate the puncture on the inside

of the tire and circle with crayon.

3. Remove puncturing object if it is

still in the tire.

4. Carefully inspect tire on a good

tire spreader, with ample light,

that will show any cracks, breaks,

punctures, damaged or broken beads.

5. Check liner for cuts, cracks, or

holes which may cause the tubeless

liner to lose air.

6. Check the injury with an

inspection awl:

a. Determine size and angle

of injury.

b. Check for ply or belt separation.

7. Reject any tire that has separation,

loose cords, damaged bead(s), or any

other non-repairable injury.

8. If the hole is simple and round,

steps 9 through 17 of the puncture

repair procedure will be successful.

NOTE: If the hole shows evidence

of fabric splitting, such an injury

cannot be properly repaired using

this puncture repair procedure. Such

an injury must be skived out and

repaired as a section (reinforced)

repair, which will maintain the

serviceability of the tire, but will

invalidate the tire’s speed rating. If

a section repair is necessary, the

customer must be advised, before the

repair is made, that the tire will lose

its speed rating, and must not exceed

operation at normal highway speeds.

9. Use a pre-buff cleaner and a

scraper to remove contaminants

from the liner in the area to be buffed

around the injury.

10. Use a 7/32”carbide cutter for ¼”

repairs to clean out the puncture.

a. Make sure that the drill follows the

direction of the puncturing object.

b. Always drill from inside

to outside of tire.



111April 2009 | MasterTechnician Online

11. Using chemical vulcanizing

cement, lightly coat at least 1/2 of

tapered end of the repair plug. Install

the plug in the prepared puncture

according to the manufacturer’s

instructions. Trim the liner side of the

plug slightly higher than the surface of

the liner without stretching the plug.

12. Center the patch (or patch

template) over the injury without

removing the backing. Adhere to

patch or template instructions, as

to positioning as related to bead

location. Using a marking crayon,

mark around the outside edge of

the patch, approximately 1/4” larger

than the patch.

13. Buff the liner and plug at the

puncture location. The buffed area

should be slightly larger than the

patch. The buffed surface should be

finely grained (RMA 1 or 2 texture)

and even for proper bonding. Use

care to prevent burning the rubber

with the buffing tool. Do not buff

through the liner. Do not buff into

the marking crayon.

Clean the buffing dust from the tire

using only a vacuum or brush. Do

not use gasoline or other petroleum

solvents on the buffed area.

Coat the buffed liner surface and

the patch with one evenly applied

coat of chemical vulcanizing

cement in accordance with the

recommendations of the repair

materials manufacturer. Allow the

cement to dry thoroughly. Do not

touch the cemented areas.

Install the patch with the beads

of the tire in the relaxed position.

Position the patch over the puncture

according to the markings on the

patch. Stitch the entire patch starting

from the center, keeping the strokes

close together to avoid trapping air

under the patch.

17. Cut off the protruding end

of the plug about 1/8” above the

tread surface.

FINAL INSPECTION -- The repair

must seal the inner liner and fill

the injury. After remounting and

inflating check the repair, both beads

and valve with a soap solution to

assure a complete seal.


A shop called me in to investigate a no-start condition on a 1996

Dodge Caravan with a 3.3L engine (Figure 1). This shop only had a scan tool in its arsenal of diagnostic equipment. No scope, no graphing meter combined with a component tester, not even a repair information system. With no codes in memory, the techs resorted to the “feels like” tactic. They used their best instincts to replace parts associated with their visual inspections and old-school test procedures.

by John Anello

The Auto Tech on Wheels tells us how he used high-tech means

to justify trans removal to find the real cause of a no-start

Figure 1

Another Mystery Solved:


Bad PCM, but why?

The spark tester they were using

only showed spark on one coil, so the

list of parts replaced included the coil

pack, crank sensor, cam sensor and a

PCM. The old PCM was bad due to a

damaged coil driver that was holding

one coil primary constantly on. I’ve

seen this many times in the field

caused by a bad coil assembly with a

shorted coil primary winding. So, I

could justify their replacement of the

coil assembly and the PCM, but the

vehicle still wouldn’t start. This shop

is not alone in the way it diagnoses

cars. All too often I cater to this type

of shop, and I try my best to educate

on-site how important it is for the

technicians to keep themselves up to

date on training and to have the proper

equipment available for performing

the tasks that will save them time and

avoid replacing perfectly good parts.

Figure 2

http://www.mastertechmag.com/articles/2009/June/wheelfortune_figure2L.jpg


This will obviously make them better

technicians in the long run. It’s never

too late to step up and take it to the

next level. The worst thing in any

business is to let technology surpass

you. You will only find yourself stuck

in the past with not much of a future

ahead of you.

When I arrived at the shop I attempted

to start the car, but it only spit back a

few times as if it wanted to start. The

tech told me that #2/5 ignition coil was

the only one firing during cranking.

The other coils did not fire at all. At this

point I decided to hook my scope up to

some selected signal lines to get a visual

concept of what was going on exactly. I

used my EScope Limited 4-trace scope

and placed my channels on the cam

sensor and all three coil drivers. As I

cranked the engine, I could see that the

cam sensor was providing the proper

signal pattern, but the PCM had a

problem controlling the coil drivers

(Figure 2). One driver attempted to

Wheel of Fortune

Figure 3



ground the coil while another driver

was held on for as long as 600mS of

on-time. By current ramping the one

working coil against the crank and

cam signals (Figure 3) I could see that

the coil driver was maintaining about

8.5 amps of current for almost one

camshaft revolution. There is no way

any driver would hold a coil primary

that long unless that driver was in love

and just did not want to let the coil go.

It was a relationship that went bad,

and no one was around to give advice

to just let go. That got me wondering

if this might have caused the failure of

the coil driver in the old PCM.

Out of synch

This erratic coil operation could

only be caused by a defective PCM

with an internal driver failure, a

corrupted crank/cam signal input,

or a crank/cam sensor correlation

problem. The cam and crank sensors

Figure 4



Wheel of Fortune

seemed to be producing the proper

patterns with correct amplitude,

but I needed to compare their synch

correlation. I used my Ace Misfire

crank/cam waveform database and

pulled up a known-good crank/cam

pattern for this vehicle (Figure 4). You

can see how the cam sensor pattern

repeats the 1-2-3-1-2 pattern while

the crank signal repeats the 4-4-4-4-4-

4 pattern. It is between where the cam

pattern ends and begins that there

should be equidistant 4-4 patterns. I

imported the cam sensor signal into

the measuring section of the scope

(Figure 5) and placed cursors to show

one complete event of the cam sensor.

By hitting the Mark Camshaft button,

the program automatically placed five

purple cursors on the screen creating

four divisions each representing 180

degrees of crankshaft rotation and

five smaller purple cursors creating

six subdivisions each representing 30

degrees within each 180 division.

Figure 5


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Wheel of Fortune

Figure 6

I superimposed the crank signal on

top of the cam signal and zoomed

in on the end and the beginning

event of the cam signal (Figure 6).

Notice how the crank signal has

shifted at least 30 degrees to the

left. This indicated that the crank

and cam sensors were not properly

synched. The cam sensor indexed

off the front of the engine while the

crank sensor indexed off the torque

convertor at the rear of the engine.

Now, I had to decide whether this

was caused by a problem in the front

or rear of the engine. With 108,000

miles on the clock it was a better sell

from a maintenance point of view to

disassemble the front of the engine to

inspect the timing chain components

than it was to pull the transmission

to check the flywheel assembly. The

cause at this point could be a jumped

timing chain, sheared crank keyway,

sheared cam gear roll pin, or even

a damaged flywheel. There was no

flywheel noise while cranking the



engine, so where do you start with

this dilemma without having to

spend unnecessary labor?

Cylinder pressure

The answer to this question is a

new test procedure I’ve been using to

check valve train problems that uses a

simple 300 psi pressure transducer. You

remove the spark plug from a selected

cylinder and install a hose adapter to

accommodate the pressure transducer.

Next, you place a spark tester on the

plug wire of that same cylinder, put an

inductive clamp around the plug wire

and crank the engine. The resulting

patterns will show you a peak-to-peak

cylinder pressure rise representing a

720 degree crankshaft event and an

induction square wave representing the

spark event in the cylinder. You then

place your cursors on the compression

peaks, select the Mark Camshaft button

and look at where the purple cursors

Figure 7



are laid out. The lowest point (u-curve) before BDC of the power stoke is where the exhaust valve begins to open. This I have found to be about 30-45 degrees before BDC of the power stroke on most of the cars I have been checking. The waveform pattern (Figure 7) shows the exhaust valve to be opening close to 30 degrees before BDC of the power stroke. The spark was occurring only once in the cylinder when it should have occurred twice. The ignition only fired the waste spark and fired wrong at about 40 degrees after TDC of the

Wheel of Fortune

Figure 8

exhaust stroke. This was due to the incorrect coil primary control caused by the crank/cam correlation problem.

Known good

By viewing a known-good pattern of a 1997 Dodge Caravan with a 3.3L (Figure 8) you can see that the exhaust valve opening event is happening at about 30 degrees before BDC of the power stroke. This file was from a running engine,



so the advance timing was added to the base timing to bring the timing to about 25 degrees (always use the first rise of the inductive clamp square waveform) before TDC of the compression stroke for ignition spark and 25 degrees before TDC of the exhaust stoke for waste spark. This method is such a great way to learn about combustion strategy and, at the same time, give you another weapon in your arsenal to fine tune your diagnostics as far as which direction you want to head in. Even if this had been a dual cam set-up, you would have had no problem in finding out which cam was off from spec without even pulling a timing cover. Just by having this information validated from doing other known-good vehicles, it was safe for me to instruct the garage to pull the transmission and inspect the flywheel.

About an hour later the shop called to tell me that the transmission was pulled and I needed to come back to see the damage they found. When I arrived there at the end of my day, I was amazed. The center of the flywheel was completely cut out from the rest of the flywheel like a cookie would be cut out of rolled dough. The center piece spun slightly and wedged itself in place (Figure 9). The

amazing thing was that there was no noise associated with this flywheel while cranking. I helped the garage remove the flywheel and placed it on the ground. I pushed on the center piece and it fell out. The only thing holding these pieces together was the center thrust plate and flywheel bolts.

This flywheel was like a wheel of fortune just making the shop spend time and money without a cure in sight, and at the same time sending them on a wild goose chase. It held the torque converter and provided the crank triggers necessary to start the engine. Who would ever think a flywheel could break clean and spin, yet go undetected? I hope this story sheds some light on the value of a scope, which allows you to see beyond the normal reach of a scan tool.

Figure 9


Even though this

system is typically

trouble-free, it’s on

so many vehicles you

need to know about it

GM “U” Body Automatic Level Control

by Greg McConiga

Every so often somebody

actually thinks ahead and

designs a system to overcome

a problem that just might arise.

Appearing in two versions on GM’s

second and third generation kid-

haulers (1997 to current production

Venture/Uplander, Transport/

Montana, Terraza and Silhouette,

as well as the 2001-2005 Aztec and

2002 and up Rendezvous), the rear-

only automatic level control system

came about because someone

thought about how these famously

utilitarian and cavernous family

cargo haulers would actually end

up being used. I had one, and it

transported everyone and everything

at one point or another. From four-

by-eight sheet stock to ladders and

tools, it cheerfully moved everything

we stuffed into it while getting about


Here’s what you see with all the fasteners removed and the compressor hanging from its safety bracket. The drier, relay, harness and compressor are in one package.

seat are candidates, as well as our topic

du jour, the minivan and its SUV

spinoffs. If you think about it, you’ll

see that automatic rear level control

systems are actually safety systems

-- crash safety, vehicle dynamics and

braking are all dramatically affected

by vehicle trim.

In a collision, maintaining proper

ride height is one key to making

19 mpg city and 24 highway – not

bad for a blunt-nosed, flat-sided

aerodynamic nightmare on wheels.

Level’s important

Rear level control systems are likely

to appear where vehicle loading varies

considerably. Large cars with room

for three plus-size people in the back



sure that all parties involved are

properly protected. In a rear hit, a

low riding rear bumper could allow

the colliding vehicle to ride up over

the rear sill and into the cabin area.

In a frontal impact, if the front of the

van/SUV is tipped up, the colliding

vehicle could dive under, perhaps

decapitating the occupants or causing

an unintended “launch” of the van/

SUV. Additionally, having your tail

dragging can bypass the crush and

crumple zones that are built around

the “normal” impact areas of either

front or rear, thus circumventing

the impact reducing effects that are

engineered into those controlled

crush zones. And don’t forget

what happens to the headlights!

Blinding oncoming drivers is just

plain inconsiderate at best, but it’s

dangerous to family and friends when

you can’t see where you’re going on

dark twisty roads because you’ve got

the headlights tipped up to the “tree-

top inspection” setting. Extra weight

affects handling even when trim is

maintained, and that’s bad enough,

The ALC relay is mounted to the compressor bracket assembly under the left rear of the vehicle.

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but tilting the weight distribution

rearward and off the front tires

makes a mildly under-steering

vehicle misbehave even more. Vehicle

handling and roll characteristics also

change for the worse, as does braking

performance. All good reasons to

keep the vehicle at or near a standard

trim specification.

There are two variants of the system,

one from 1997 until 2002, and another

from 2003 through the current model

year. Both systems are available with

or without the inflator option, which

allows you access to the onboard air

compressor for chores like pumping

up tires or inflatable toys. From 1997

until 2002, the system had no self-

diagnostics, but starting in 2003 a

limited self-diagnostic capability was

embedded into the height sensor.

The actual function of both systems is

identical, with the exception of being

able to flash codes at the inflator


Here’s the brains of the outfit. The ALC sensor does nearly all the work. The sensor mounts to the body, the non-adjustable arm to the axle and the electronics do the rest.

control switch, and the addition of

a circuit to the height sensor that

controls the inflator solenoid valve,

so we’ll discuss the later system in this

article. When working on the first

generation system you’ll simply stick

to symptom-based diagnostics and

follow the appropriate flow chart.

Components

The air shocks are conventional

with the addition of a rubber sleeve

that’s attached between the dust

tube and the reservoir, which creates

a flexible air chamber -- you’ll

never see them leak unless the boot

fails. Minimum residual pressure is

maintained at eight psi by the air drier

assembly. The shocks are connected

to the compressor by plastic lines and

couplers that are double o-ringed and

The inflator adds a switch and the inflator control solenoid to the system. With the inflator option you also get limited self-diagnostic capability.

Click to enlarge.

http://www.mastertechmag.com/articles/2009/May/image/gmairsuspschematicL.jpg



The rear shocks are standard design with the exception of the added air bladder. Don’t be tempted to replace the air shock system with standard shocks for all the safety reasons previously mentioned. No point in asking for additional liability exposure.

retained by clips. The compressor

is a 12 volt permanent magnet DC

motor, positive displacement piston

compressor with a serviceable

cylinder head assembly containing

inlet and outlet valves and the exhaust

vent solenoid. The compressor is

mounted under the left rear corner

of the vehicle and is tucked up into

the left rear quarter panel area.

The electronic height sensor is the

brains of the outfit and attaches to

the body while the non-adjustable

linkage attaches to the rear axle. The

height sensor controls the compressor

exhaust valve, the inflator solenoid

valve and the compressor, and houses

the self-diagnostic electronics and

compressor run logic. An inlet filter

that limits the ingestion of dirt is a

simple foam filter that snaps into a

hole in the frame rail. On the discharge

side the desiccant-type drier mounts

to the top of the compressor assembly

between the compressor discharge

and the plastic lines that connect to

the shocks. On those systems with

an inflator system, there is an inflator

control panel containing the switch

and a high pressure air supply port

in the left rear quarter panel under


(Right) The inflator solenoid assembly is mounted on the backside of the inflator control panel, located in the left rear inside quarter of the vehicle. (NOTE: Color is added for viewing enhancement only.)

(Below) Three bolts, one electrical connector and two air connections later and the whole shootin’ match is on the bench. Be prepared to work a bit to get the bolts loose, remember this thing is right behind the left rear wheel. You can see the compressor ground, the exhaust solenoid in the head, the drier and part of the tabbed bracket that holds it in the frame when the bolts are removed.



a removable cover. The inflator

solenoid is attached to the backside

of the inflator control panel in the

left rear.

Operation

At key up the height sensor checks

ride height. If it’s within four

millimeters of the set point, there’ll be

a 30 second wait, then the compressor

runs for four seconds to guarantee

adequate reserve air pressure of eight

psi. If the vehicle is out of trim, after

20 seconds the compressor will start

and run until the desired attitude is

reached – or 255 seconds, whichever

comes first. The compressor

protection portion of the height

sensor logic limits run time to 255

seconds at each key cycle to prevent

compressor damage in the event of

a pressure leak. The start is always

The drier keeps moisture out of line and shocks. Technically it should be replaced periodically, but I didn’t find any published recommendations for replacement.

http://www.rae-service.com/rae-website/



delayed 20 seconds from the call for

ride height adjustment to compensate

for normal vehicle movement and

suspension travel, thereby avoiding

compressor short cycling or needless

starts. The exhaust solenoid valve

actuates for 1.5 seconds with each

compressor start to reduce pressure

in the compressor head cavity and

reduce startup current.

Diagnosis

The system has ten DTCs you can

call up using the inflator switch.

To extract codes, press and hold

the accessory inflator switch for

three seconds. From initiation

the self-test takes 200 seconds to

complete. The number of flashes

on the switch LED represents the

currently present codes and all

codes will flash until acknowledged

by pressing the inflator switch,

or until the module goes to sleep.

The LED will flash the first digit of

Located on the left rear inside quarter panel trim the inflator panel has an auxiliary power outlet, the control switch and an air fitting. These vehicles have a hose and inflator kit supplied with them that can stretch to reach all four tires.


1- The foam air filter clips on the end of the intake line and snaps into the frame high up to avoid water ingestion.

2- Rubber splash shield

3- Mounting bracket


the two digit trouble code at half

second intervals followed by a one

second delay and then the second

digit will flash. Each code cycle

will be separated by a three second

delay. Once the conditions that

set the code are repaired, the codes

will automatically clear when the

ignition is cycled.

Real world

This system can only be called

reliable and robust. Of all the

people I spoke with, not one saw

any significant failure patterns,

which mirrors my experience. We’ve

replaced a few lines attacked by

rodents (if someone can explain the

affinity rodents have for plastic and

wiring insulation, I’d sure like to

hear it!), and a few shock units that

were worn out, or with blown out air

bags, but that’s about it. The ability

to pump up a flat tire with your own

vehicle is a great idea (I’ve done that

at least once), and it’s nice to be able

pump up pool toys and bike tires as

well. It’s a good system that is well

executed. Really, I’m on the level!

Diagnostic Trouble Codes

DTC 11 is related to the accessory inflator solenoid, and will set for short to power, short to ground or a malfunctioning solenoid.

DTC 12 is the system okay code.

DTC 13 sets if the ride height is out of specification.

DTC 21 sets if the compressor relay coil control circuitry shorts to ground.

DTC 22 sets if the compressor relay coil circuitry opens or shorts to battery.

DTC 23 sets if the compressor runs for 255 seconds during a leveling function.

DTC 31 sets if the exhaust solenoid control circuit shorts to ground.

DTC 32 sets if the exhaust solenoid control circuit opens or shorts to battery.

DTC 33 sets if the exhaust solenoid has been energized for 255 seconds and the height sensor did not detect the proper downward movement.

As is typical, each of these trouble codes refers you to a multiple-page diagnostic flow chart to accurately complete the diagnosis.


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a mastertechmag.com online publicationApril 2009 VOL. #15 N0.1

Needle in a Haystack

Another Mystery Solved

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Inside the Insider

Five Ways to Limit LiabilityBy stepping out into the business world, every step has exposure. While you cannot stop people from suing, you can insulate your business, personal assets and wallet from most liability if you take some steps to protect yourself.

(Turn to page 1)

Human PotentialThe mind is a strange and powerful tool. Psychologists tell us some very interesting things about its function. First, 90% of its activity is subconscious.

(Turn to page 1)

In Times Like TheseSmall business is the skeleton of our economy. Businesses like ours.

(Turn to page 3)

Sole ProprietorshipIt does not matter whether the individual is just getting started in a new business or is a twenty year business veteran this question comes up on a regular basis. My answer to this dilemma has always been the same, it depends.

(Turn to page 6)

MT Business Insider Pricing MatrixBusinesses are based on percentages, but customers look at prices. How do you reconcile your business’ need to make a decent profit margin on parts with your customers’ need to pay a fair price?

(Turn to page 8)

ASE Certification: The Competitive AdvantageOne of the most powerful influences on choosing a repair facility is word-of-mouth recommendations from family, friends, and neighbors. Existing customers usually recommend a business based on trust and positive past experience.

(Turn to page 10)

Volume 1 | Issue 1

Five Ways to Limit Liability For Business Owners

By David V. Allen, Esq.

By stepping out into the business world, every step has exposure. While you cannot stop people from suing, you can insulate your business, personal assets and wallet from

most liability if you take some steps to protect yourself.

First, incorporate or form a limited liability company.

This requires that you file articles of incorporation, or in the case of a limited liability company (LLC), articles of organization with the Secretary of State, or whatever governmental office handles business filings in your state. Once you incorporate or form an LLC, you must hold your business out to the public as a corporation or LLC. This means

Continue p.2: Five Ways

Continue p.5: Potential

Human Potential Using What You’ve Got

by Greg McConiga

The mind is a strange and powerful tool. Psychologists tell us some very interesting things about its function. First, 90% of its activity is subconscious. Let’s define that. “Sub,” as in

“below,” and conscious, as in an individual sense of recognition of things within or without oneself. 90%! Think about that. It says if -- IF -- you are 100% in control during your waking hours, the very best you are capable of achieving is still only 10%. It’s generally agreed that a human’s learning ability is physically unlimited. Remember that a scrap of brain tissue no larger than this “o” can store more information than a computer the size of a Honda. Now, consider that an average person’s brain weighs about three pounds. How many ounces of yours do you actually use?

June 2009 | MasterTechnician Online 1

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