April 2010 MasterTechnician by Automotive Data Media

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U n intende d ABS Breakin g

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Contents

Feature Stories 08 Civic HV Battery Replacement by Paul Cortes

Quite a few techs have had experience with Toyota HV (Hybrid Vehicle) batteries, but, Honda IMA battery packs remain a mystery for many techs at independent shops.

22 On the Outside Looking In by John Anello

A Cadillac Escalade with a check engine light (MIL) needs a closer look.

42 Two Peas in a Pod by John Anello

A no-start Chevy pickup with loose screws sit together like two peas in a pod.

50 Security Issues by Kerry Jonson

Theft deterrents make sense on a new vehicle. Eventually, though, these become old vehicles that have to be repaired. How do you diagnose the GM Passkey III system that is designed to prevent the engine from starting? We canâ&#x20AC;&#x2122;t ask a car thief, can we?

Cover Story 32 Unintended ABS Braking by Kerry Jonson

There are many ways to describe slowspeed ABS activation, but once youâ&#x20AC;&#x2122;ve nailed down the symptoms, how do you go about fixing them? April 2010 | MasterTechnician Online

U n intende d ABS Breakin g

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Christopher M. Ayers, Jr. President/Publisher cayers@mastertechmag.com

Bob Freudenberger Editor bfreud@mastertechmag.com

John Anello • Steve Campbell • Paul Cortes Kerry Jonsson • Phil Fournier • Chip Keen Greg McGoniga • Tony Molla • Tom Nash Henry Olsen • Matt Ragsdale • Dave Russ Contributing Editors bfreud@mastertechmag.com

Christopher-Michael Ayers Art Director, Project Mgr. ayersc3@mastertechmag.com

Joann Turner Circulation Manager jturner@mastertechmag.com

Advertisers December 2009 AIRSEPT.............................. 49 Autel Auto Link................... 39 Autologic US....................... 11 BMW..................................2-3 BASF.................................... 41 Castrol................................. 47 CRP...................................... 13 Dayco..................................... 6 GRACO................................ 29 Henry Rifles......................... 53

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Master Technician Magazine 486 Pinecrest Rd. | Springfield, PA | 19064 P.484.472.8441 • F.484.472.7460 If you have a letter to the editor, a Tech Tip or story idea, Email: bfreud@mastertechmag.com, or go to: www.mastertechmag.com. Master Technician is published by Master Technician, 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 & technicians. Contact ayersc3@mastertechmag.com for more information. All other content on is available on a subscription basis. Visit www.mastertechmag.com for subscription information.

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April 2010 | MasterTechnician Online

C i v ic HV Battery Replace m e n t

More Hands-On Hybrid Info:

Civic HV Battery Replacement

by Paul Cortes

hese days, quite a few techs have had experience with Toyota HV (Hybrid Vehicle) batteries, either during handson training, or while repairing customers’ cars. Honda IMA battery packs, however, remain a mystery for many techs at independent shops. It’s not due to lack of failures. In our shop, we’ve diagnosed several battery module failures, but most of them have been covered under the extended warranty on the Insight, or under the standard 8/80 warranty. The first time we encountered a failed IMA battery module that was out of warranty, our dealership refused to sell us the battery citing 8

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training and safety concerns. After some back and forth, they finally admitted they had made a mistake, but by then it was too late and we had lost the sale. We just recently replaced our first IMA battery on a 2003 Civic. It was a car referred to us from another shop because they weren’t comfortable doing the job. After replacing the battery pack, I felt kind of bad for them. The job was very easy, much easier than replacing the battery pack in a Prius. The referring shop is good with talented techs. I know for a fact they would have had no trouble replacing the battery pack if they had tried. So, in my opinion the

Posted to mastertechmag.com April 15, 2010 Key Word: Civic HV Battery

The PGM-FI codes P1600 and P1601 indicate a problem with the IMA system and do not need to be investigated. The SRS code 07-2 was caused by a bad SRS control unit and is unrelated to the other codes.

only thing that held them back from taking on an easy and profitable job was fear of the unknown. The purpose of this article is to demonstrate how easy IMA battery replacement really is, so that good shops won’t give away good work just because they don’t know what to expect, or because the flat rate time seems low.

Equipment You will need the factory scan tool, the Honda HDS. The HDS used to come in three flavors: Tablet PC,

Pocket PC, and Standard PC. Now, the HDS only comes in the PC version. The PC interface device – a box with two cables, one that connects to the laptop and the other to the OBD II connector – is currently the GNA600, which sells for about $2000. You’ll also need software for the laptop, which runs about $840 per year. Finally, you’ll need a subscription to Honda Service Express, Honda’s information website. The website covers Honda and Acura products and is a bargain at only $350 per year. If you have an LSID (locksmith license), you can subscribe to the Security Professional version for $500 April 2010 | MasterTechnician Online

C i v ic HV Battery Replace m e n t per year. If you work on Honda or Acura, you’re handicapping yourself by working without these resources, so regardless of whether or not you’re interested in replacing IMA batteries, this equipment will quickly pay for itself.

Diagnosis Diagnosis is almost disappointingly simple. Pull the codes, in this case a P1447 and P1449. After a quick search on Service Express, you’ll find a couple of surprisingly short flow charts. Both consist of only one line, “Replace battery module.” The 144-Volt IMA battery is made up 20 7.2V cells tied together in series. Voltage is monitored at 12 points among the cells. The Motor Control Module (MCM) compares the lowest segment voltage to the highest segment voltage. If the difference is too great, a code P1447 will set. Toyota requires a “manual” verification of excessive voltage spread under load using scan data. Honda says finding a code P1447 is enough to condemn the battery. It makes for a quick, if not intellectually satisfying, diagnosis.

10 MasterTechnician Online | www.mastertechmag.com

The code P1449 is an indicator of poor battery capacity. The MCM monitors the minimum and maximum battery voltage and computes the electrical current value during operation to calculate the battery capacity. Think of it like this: When the IMA motor is drawing current, the MCM monitors the rate and level of the decrease in voltage, just like a load test on a 12V battery. When the IMA is acting as a generator, the MCM monitors the rate and level of the increase in voltage, just like a five-minute charging test on a 12V battery.

Obtaining a battery Battery modules can be purchased through any Honda dealer (don’t let them tell you otherwise!). The old battery must be returned in the custom-built shipping box they provide (Image 2). Keeping the old battery is not an option. There is an additional shipping charge on the battery, so be sure account for that when quoting the job. There is also some paperwork that must be completed. The Honda IMA battery reman program requires a copy of the dealer invoice, a copy of the repair order, and a completed IMA

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C i v ic HV Battery Replace m e n t 2

Custom-built shipping box provided by the dealer.

Battery Module Return form, which asks for three pieces of information: 1. What was the customer complaint? (In this case, the IMA and Check Engine lights). 2. Did you duplicate the complaint and what codes were stored? (In this case, P1600, P1601, P1447, and P1449). 3. Were there any other symptoms or conditions? (In this case, no). Failure to complete the paperwork results in a $50 “diagnostic fee,” so it makes sense to spend a couple of minutes jotting down some notes and photocopying. 12 MasterTechnician Online | www.mastertechmag.com

Read the instructions Replacing the IMA battery is some pretty basic R&R work. However, there are three good reasons to read the instructions. First, it is possible to electrocute yourself. Second, the two minutes you spend looking up and reading the procedure will save you time when you do the job. Third, you’ll need to look up the torque specs anyway, so you may as well read the instructions before you start. The IMA battery lives behind the rear seat back. Honda’s instructions include hyperlinks in blue (Image 3). For instance, on this page it says, “Make sure you’re familiar with IMA service precautions before doing repairs or service.” So, if you’re not sure that you are, you can click on the link to find out what you should know before you start.

Removing the IMA battery The first step is to disconnect the 12V battery. This is necessary for safety and to prevent possible damage. Next, remove the seat bottom, then the seat back. Thankfully, most Japanese cars

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April 2010 | MasterTechnician Online

C i v ic HV Battery Replace m e n t 3

Honda’s instructions include hyperlinks in blue.

have more or less the same design, and the Civic hybrid is no different. The front of lower cushion is held in place with two clips. Just pull straight up and they will pop out (Image 4). The rear of the lower cushion is held in place with a single bolt near the center (Image 5). Once the bottom cushion is removed, you’ll have access to the two bolts holding the back cushion in place (Image 6). With the seat out of the way, there’s plenty of room to work, even for a tall guy (Image 7).

from this point on -- you’re a goner regardless. Remove the two bolts on this cover and you’ll find the IMA switch, which is just like a light switch. Remove the red locking clip, flip the switch to off, and reinstall the red locking clip (Image 9). This will prevent the switch from being turned on while you are working on the car. Honda says to wait five minutes after flipping switch before removing the Intelligent Power Unit (IPU) cover. This will give the capacitors time to discharge.

The “HIGH VOLTAGE, You will be killed or hurt” warning is a friendly indicator you are getting closer to the IMA battery (Image 8). Since it’s an unconditional statement, we may as well proceed, since it apparently makes no difference what you do

Next, remove the IPU cover. It’s held in place by 10 T30 Torx bolts and one trim clip right next to the switch (Image 10). When the switch is in the “ON” position, it blocks the trim clip so you can’t remove it. Honda does not have an interlock system

14 MasterTechnician Online | www.mastertechmag.com

With the seat out of the way, there’s plenty of room to work.

Above: “HIGH VOLTAGE, You will be killed or hurt” warning.

IMA switch: Remove the red locking clip, flip the switch to “off,” and reinstall the red locking clip. April 2010 | MasterTechnician Online

C i v ic HV Battery Replace m e n t like Toyota, so if the “clipinterlock” has been defeated because the last technician didn’t put it back, it’ll be up to you to remember to flip the switch before removing the cover. The IMA battery is a black box with two straps on the right (Image 11). Before touching anything, you’ll want to verify the power is off. Honda says there should be less than 30V, but there is no reason you shouldn’t have 0V or pretty close to it (Image 12).

things before unbolting and removing the IMA battery. Start with the MCM connector (Image 13), then remove the three other connectors as well (Image 14). Gently squeeze and

You’ll need to disconnect a few

10 IMA battery is a black box with two straps on the right.

The IPU cover is held in place by 10 T30 Torx bolts and one trim clip right next to the switch. 16 MasterTechnician Online | www.mastertechmag.com

Verify the power is off. Honda says there should be less than 30V, but there is no reason you shouldn’t have 0V or pretty close to it.

Start disconnecting the MCM connector first.

Remove the other three connectors as well.

remove the harness routing clips and remove the capacitor ground bolt (red arrow) (Image 15). Remove the battery cables and tape the ends (Image 16). Honestly, Iâ&#x20AC;&#x2122;m not sure why. There will be no power at these cables while the car is sitting motionless in the bay with the key off and the battery disconnected. However, the instructions are there to keep you safe and prevent damage,

Remove the capacitor ground bolt (red arrow) April 2010 | MasterTechnician Online

C i v ic HV Battery Replace m e n t so itâ&#x20AC;&#x2122;s best just to follow them. One connector must be removed from its mount before it can be separated (Image 17), similar to many Honda O2 sensor connectors. The IMA battery module is held in place with four bolts and one retaining bracket (Image 18). It seems like Honda always considers ease of repair when they are designing a car. I doubt these straps are used during manufacture, but they sure are handy when removing the battery (Image 19). The battery is a little heavy, but I was able to remove it by myself fairly easily. The Gen 1 Prius is about twice as heavy and I always get some help to remove it from the car. Unlike the Prius, there is no need to transfer any components other than the switch lock clip. Just grab the new battery and put it in the car, then put the old battery in the box to send back to Honda (Image 20). I would strongly recommend using a torque wrench for the battery cables (Image 21). The spec is 7.2 ft.lbs, which is lower than most torque wrenches will read accurately. So, use an in.lb. wrench instead. 12 x 7.2

18 MasterTechnician Online | www.mastertechmag.com

Remove the battery cables and tape the ends.

This connector must be removed from its mount before it can be separated

The IMA battery module is held in place with four bolts and one retaining bracket.

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April 2010 | MasterTechnician Online

C i v ic HV Battery Replace m e n t ft.lbs. = 86.4 in. lbs. I used common sense and a 3/8 in. electric impact wrench for everything else.

Itâ&#x20AC;&#x2122;s pretty basic, but often overlooked: I like to connect all of the seat belts to make sure none are still stuck under the seat or twisted any time I remove a seat (Image 22). And thatâ&#x20AC;&#x2122;s it. Replacing the IMA battery is easier than most brake jobs, radiator or CV boot replacement, and a whole lot cleaner!

Straps make for easy battery removal.

No need to transfer components. Simply replace the old battery with the new, and ship back to Honda.

Strongly recommended to use a torque wrench for the battery cables.

Often overlooked- Connect all of the seat belts to make sure none are still stuck under the seat or twisted any time the seat was removed. 20 MasterTechnician Online | www.mastertechmag.com

April 2010 | MasterTechnician Online

Ou n tside the Ou Looking tside Looking In In

by John Anello

was called in to a shop that had a complaint of an illuminated check engine light (MIL) on a 2005 Cadillac Escalade with a 6.0L V8 (Figure 1). The shop was wrestling with an IAT temp code, but was hesitant about changing the MAF sensor due to the low mileage (18,000) on the vehicle. The IAT sensor wiring at the sensor checked out fine, but the shop was still seeing a negative value on the IAT sensor reading on the scan tool. The Intake Air Temp sensor on this vehicle is incorporated within the MAF sensor assembly. Hanging one of these sensors on the engine without any results could

22 MasterTechnician Online | www.mastertechmag.com

prove to be a costly mistake. If you purchase a part and it doesnâ&#x20AC;&#x2122;t resolve the problem, the wedding ring goes on and youâ&#x20AC;&#x2122;re now married to the vehicle. It becomes a love/hate relationship with no turning back because you have now

Figure 1: 2005 Cadillac Escalade with a 6.0L V8 and illuminated check engine light (MIL).

Posted to mastertechmag.com April 15, 2010 Key Word: Looking in

Figure 2: First vehicle scan pulls up a code P0113.

committed yourself to fixing the car. You could, however, choose divorce, but that would only lead to you having to eat the unwanted parts and losing the trust of your customer, who may label you as a parts changer. The IAT sensor itself varies its resistance according to the ambient air temperature it is exposed to. With the negative-coefficient type, its resistance value will increase as temperature decreases. The PCM supplies the IAT sensor with a fivevolt reference feed and a reference ground. The resistance of the sensor

will rise when it encounters incoming cool air, and it will move the five-volt ref line further away from ground. This can be easily seen if you were to graph an IAT sensor and simply snap the throttle to allow a rush of cool air to enter the MAF sensor housing. I first scanned the vehicle (Figure 2) and pulled a code P0113. This indicated that the circuit was high above the threshold allowed for the sensorâ&#x20AC;&#x2122;s range of operation. By also looking at the freeze-frame (Figure 2), you can see that the engine was at an operating temperature of April 2010 | MasterTechnician Online

O n the Ou tside Looking I n 176 deg. F. when the IAT sensor failed with a reading of -38 deg. F. The freeze’frame information holds a lot of value for a technician by allowing him or her to actually see what events took place at the time of the failure. It’s important for a technician to have a set of parameters to view, such as rpm, coolant temperature, throttle position, air flow rate, fuel trim information, and even vehicle speed. This can provide criteria that may by needed in order to duplicate the problem, especially if it’s not present at the time the vehicle is driven to

the shop. There are a lot more freeze frame PIDs available on newer OBD II systems, and this list will only get bigger in the future. To verify the IAT failure, I selected the IAT parameter in digital format (Figure 3) and I could see the -38 deg. F. value on the scan tool. What was also interesting was that the scanner pointed out that the vehicle was over-charging at 15.3 volts. This can be seen in the left side bar of the screen shot (Figure 3). At this point, I wanted

Figure 3: To verify the IAT failure, I selected the IAT parameter in digital format and I could see the -38 deg. F. 24 MasterTechnician Online | www.mastertechmag.com

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April 2010 | MasterTechnician Online

O n the Ou tside Looking I n to concentrate only on the IAT temp failure, and deal with the charging system problem later. It is not uncommon for a vehicle to have multiple problems during a visit to a shop. You need to concentrate on fixing one problem at a time, or you will be spreading yourself thin by being all over the diagnostic map. This is unless you feel that certain problems may be related to one root cause creating a chain reaction, such as a misfire code and O2 code created by lean operation due to a bad fuel pump.

I went back to the IAT sensor connector to take a reading with my component tester and found the IAT sensor line to be at 5V (Figure 4). According to the component tester screen and taking into account the high temperatures within the engine compartment, the IAT value should have been well below 4.0 V. The only way the reference voltage could be at 5V is if the reference ground was bad, or the sensor was on an open circuit. I checked the reference ground at the sensor connector and found it to be well below 100mV, so my next move

Figure 4: The IAT sensor line to be at 5V 26 MasterTechnician Online | www.mastertechmag.com

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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

April 2010 | MasterTechnician Online

O n the Ou tside Looking I n was to unplug the sensor to check the integrity of the connector. It is not uncommon for a connector to have a collapsed pin, or even a broken stranded wire so itâ&#x20AC;&#x2122;s only being held together by the insulation. When I pulled the connector (Figure 5) I was surprised to see only four pins showing at the end of the connector. The IAT reference ground had backed out of the connector (Figure 6).

Figure 5: AFter pulling the connector, only four pins show at the end of the connector.

At this point I simply pushed the pin back in place and reinstalled the connector. I took another reading with my component tester (Figure 7) and I could see the IAT sensor value came back down to the proper level of about 2.5V. I erased the codes and started the vehicle up again to viewthe IAT sensor value, which was now reading about 86 deg. F. (Figure 8). To my surprise, the charging voltage also came back to a normal reading of about 14.66V (Figure 8). The garage was very relieved to find out that the problem turned out to be a simple fix with no major parts purchased. This is the kind situation where customers would be happy to pay for diagnostic time and the repair of a harness connector knowing that you saved them money

28 MasterTechnician Online | www.mastertechmag.com

Figure 6: The IAT reference ground had backed out of the connector.

April 2010 | MasterTechnician Online

O n the Ou tside Looking I n

on unnecessary parts that could not be returned to the jobber. The connector pin could have been pulled out when someone was replacing the air filter and inadvertently tugged on the MAF harness connector. It was an unforeseen problem that could be mistaken for a component failure. But letâ&#x20AC;&#x2122;s get back to the high charging volts of the alternator, and why it was now okay. I gave this one a lot

of thought and just applied some logic to the voltage readings I saw on the scan tool. The PCM saw the ambient temperature of -38 deg. F. and decided to up the charging rate of the alternator to keep the electrons within a very cold battery moving. This was a normal reaction of the PCM to counteract the frigid ambient conditions it believed the vehicle was exposed to. Once I repaired the problem, the PCM saw the correct ambient temperature and

Figure 7: Another reading with the component tester and the IAT sensor value came back down to the proper level (~2.5V).

30 MasterTechnician Online | www.mastertechmag.com

lowered the charging voltage back to a normal state. If you’ll remember, Chrysler also used the IAT sensor to control charging voltage according to ambient temperature. This is why the company renamed its IAT sensor a “battery temp sensor” and relocated it much closer to the battery. Gathering information and not jumping to conclusions without checking all the possibilities is crucial to a successful diagnosis. Testing a connector should not just

involve external examination by back-probing the wires, but also an integrity check of the mating plug for proper fit, orientation of wiring at the plug, and the wiring strands leading into the connector pins. There are even tool makers who will sell gauge pins to test the fit of a female connector. Don’t be the guy on the outside looking in. Be the guy on the inside looking out as well. I hope this story hits home with a lot of techs out there in the trenches.

Figure 8: Both the IAT sensor value and charging voltage return to normal readings.

April 2010 | MasterTechnician Online

U n intende d ABS Breakin g

Unintended ABS Braking

by Kerry Jonsson

There are many ways to describe slow-speed ABS activation, but once you’ve nailed down the symptoms, how do you go about fixing them?

ntilock Brake Systems (ABS) have been common for almost 30 years. You would think they would be problemfree by now. Well, thankfully from a service business point of view, they’re not. Typically, your customers have you take a look at the vehicle to find out why the ABS light comes on. Their worry is about possible serious safety issues. Most of the time, motorists never even notice the ABS at work. Even after panic stops, they don’t realize that a computer was monitoring the sensor inputs and activating the solenoid outputs in order to maintain traction. We just hope they were able to stop in time! 32 MasterTechnician Online | www.mastertechmag.com

But what do you do when the ABS warning lamp is not on? Do you still have a problem? Should the ABS system be activating at such low speeds? How can you figure out what’s wrong? Remember, on most systems, scan tool data will no longer be available after a certain speed. In this case, this isn’t so bad because the problem happens at low speed when the vehicle is approaching a full stop. The customer may notice a pulsation in the brake pedal. During a panic stop in low traction situations, this is normal. Lowspeed ABS activation should never happen when traction is normal.

Posted to mastertechmag.com April 29, 2010 Key Word: Unintended ABS

Understanding the Problem How are you going to approach the problem? The first step is to get a clear description of what’s happening from the customer. Then, go for a test drive with him or her along. The one thing you want to avoid is to start diagnosing the ABS when the real cause of the pulsation is brake disc thickness variation, or perhaps even a bad universal joint. Actually, the ABS computer and controller are doing what they were designed to do -- just under the wrong conditions. The computer monitors the speeds of individual wheels (or, axle speed on RWAL systems) and releases the brakes on any wheel that

is rotating at a different speed from the other three. That’s exactly what is happening here. The ABS module “feels” one of the wheels is traveling at a slower speed than the others, when, obviously, the wheels are all spinning at the same rate on dry pavement. The customer is not complaining about a loss of traction, just a funny feeling in the brake pedal. Since the ABS computer has been fooled into believing that one of the wheels is not spinning at the same rate as the other three, it will activate the solenoids controlling the brake fluid pressure to the offending caliper. What we need to realize is that a wheel speed sensor is “lying” to the ABS (Below) When dealing with a low-speed ABS activation complaint, you will need to figure out which wheel is at fault. Graphing the wheel speed sensors is a great way to save time. Notice that the left front wheel has spikes in the graph as it slows down. This wheel signal that’s causing the trouble. April 2010 | MasterTechnician Online

U n intende d ABS Breakin g computer. None of the wheels have lost traction, but the ABS computer “thinks” one has. All you have to do is find out which wheel it is and fix it. This is easier said than done. Since there is no malfunction with system operation, a trouble code will not set.

The First Steps We have all been guilty of it at one time or another. We have all spent too much time diagnosing and testing a car only to find that a simple visual check would have led us to the same conclusion. So, start here first. Since the ABS relies on all the wheels traveling at the same speed, it is necessary for all wheels to have tires of the same diameter. We know this sounds simple, but it’s more than just a different size tire numerically. Two other factors affect

tire diameter: inflation pressure, and tread wear. ABSs are so sensitive these days they can detect and react to small differences. One good question you need to ask your customer is, “Were the tires just replaced?” Then, walk around and check the sidewall info and inflation pressure of each tire. In extreme cases, you may need to take a flexible tape measure and actually measure the physical circumference of the tires. Any significant difference in tire circumference can be detected by sophisticated a modern ABS.

Now Things Are Getting Serious Once the simple stuff is out of the way, we can look a little closer. One of the first tools we reach for when

(Above) One of the first tests to be performed on a wheel speed sensor is for resistance. This should only be done on pulse generator-type sensors. Newer “active” wheel speed sensors are of the Hall-effect type and cannot be resistance tested. 34 MasterTechnician Online | www.mastertechmag.com

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April 2010 | MasterTechnician Online

U n intende d ABS Breakin g a car comes in is our scan tool -when it doubt, scan it! In this case, it may actually help diagnose the problem even if there are no DTCs in the system. Data itself can be very useful while testing this symptom. One problem scan data has always had is the relative slow refresh rate. Most scan tools these days have two abilities that we feel do not get used often enough. Number one would be data recording. You can record the data while you’re driving and review it when you get back to the shop frame-by-frame. This is much safer than watching the screen while you’re driving, especially under braking.

The second feature modern scan tools have is the ability to graph the data. With every bit of data being displayed over a period of time,you can now easily monitor sudden changes. This can also be accomplished with an oscilloscope if it is an electrical signal, but this can now also be done with scan data. You can look at the wheel speed sensor wave form with your scope, but you may be able to find the problem by graphing all the wheel speed sensor signals and looking for changes in their readings. Once again, you must realize that just because the data shows a dropout of the problem wheel speed sensor this does not always mean you should throw a sensor at the car. It does let you know which wheel is the problem, but you should back up your preliminary testing with more in-depth analysis.

We always say, “Computer’s don’t know resistance from a hole in the head!” The ABS module looks at voltage. We should be testing for the same AC voltage the module looks for. In this case, the sensor is putting out almost 2/10ths of a volt. Compare this to the other side and see if it’s the same. 36 MasterTechnician Online | www.mastertechmag.com

Digging A Little Deeper

test. Next, you should test the sensor dynamically.

While the scan tool did help isolate which wheel is the problem, you should take your diagnosis a step further. Check the resistance of the problem wheel speed sensor. Most of the time, your resistance value will be within factory specifications, but they often offer too broad a range to be able to determine if you should replace a component or not. You should compare resistances between both left and right wheel speed sensors. If they are within roughly 10% of one another, probably neither will need to be replaced. The sensorsâ&#x20AC;&#x2122; static resistance is only one possible

A resistance test is static. That means the sensor is being tested with no movement. The resistance test merely checks that the windings of the sensor are intact. This does not mean the sensor will generate an AC voltage signal that will match the other wheel on the same axle. You need to test the AC voltage signal being generated by the tone wheel passing by the sensor windings. Do this by connecting your DMM just as you would for the resistance test and setting your meter to AC voltage, which is not generated until you spin the wheel. At this point, spin the wheel by hand and see how much AC

Not every vehicle puts a bias voltage on the line to check the circuit. This â&#x20AC;&#x2122;03 Chevy Venture does put out a five-volt reference on the line. If the reference voltage were interrupted, the module would set a circuit code. April 2010 | MasterTechnician Online

U n intende d ABS Breakin g voltage is produced. Then, compare this with the voltage generated at the wheel on the other side of the same axle. Usually, you should not compare AC voltage readings from back to front.

to the sensor side of the connector, connect both of your leads to the harness side of the connector and test for DC voltage. If you read five volts, you know both the reference wire and the ground are good.

What’s Next?

Pulling Out The Big Guns

If the AC voltage readings are nearly the same, you need to take your testing to the next level. Find out if the wiring between the ABS control unit and the sensor is okay. You can unplug the computer and do your resistance testing from there. You should read approximately the same resistance as the sensor has by itself,. If not, you have a wiring problem. This test may be difficult to perform depending on where the ABS control unit is located and how accessible the connector pins are. In the case of our problem vehicle, a 2003 Chevy Venture, you should be able to read a bias voltage between the two pins of the wheel speed sensor. The ABS control unit puts out a fivevolt reference on one wire of the sensor, and the other sensor wire is grounded. If the reference is shorted to ground, the computer knows there is a problem with the circuit. Instead of connecting your voltmeter leads

38 MasterTechnician Online | www.mastertechmag.com

Since you are at the wheel speed sensor, you might want to stop and do a visual exam of the tone wheels. Look for a loose tone wheel on the axle, a cracked tone wheel, and any physical damage that might increase the gap between the sensor and the tone wheel. If you don’t see anything obvious, you’ll need to put an oscilloscope on the signal wires of the wheel speed sensors and drive the vehicle. Drive in a straight line to ensure the wheels are all spinning at the same rate of speed. The waveforms should appear identical as to peak-to-peak height and cycles per second, a.k.a. Hertz. If one wave form were to be lower than the other, that would indicate a weak sensor signal. This may be viewed as wheel lock-up by the ABS computer. You can look at these signals while the vehicle is coming to a stop and see if one pattern drops out before the others.

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U n intende d ABS Breakin g On General Motors vehicles, such as this 2003 Chevy Venture, the wheel speed sensor is built into the wheel bearing. This means that the strength of the signal may change as the load on the wheel bearing changes. On vehicles that mount the wheel speed sensor on the spindle, wheel bearing play can also affect the signal. You should also look for corrosion on the surface of the tone wheel. You may need to clean it off with a wire brush. Clean the mounting surface of the speed sensor as well to insure that the sensor is fully seated and the proper air gap is maintained.

Finally . . . Keep in mind that many times the sensor may be damaged during removal, so you should warn the customer it may need to be replaced anyway. There may be a cracked tone wheel, or it may have simply come loose from the axle or hub. This may mean an axle or hub replacement instead of wheel speed sensor replacement. Take a few minutes to cover these other possibilities. Charge for the time you spend on diagnosis.

(Below) While scoping these four wheel speed sensors, you can see that the second (Green) trace has a lower signal. This will be interpreted as a locked up wheel and the ABS will try to compensate. This is the wheel you need to focus on for repair. Sometimes it will involve component replacement, but other times just cleaning the tone wheel, sensor, and mounting point will fix the problem.

40 MasterTechnician Online | www.mastertechmag.com

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April 2010 |

2 Peas in a Pod by John Anello

shop called me in concerning a no-start complaint on a 2001 Chevy pickup with a 4.3L Vortec engine (Figure 1). It had 232,000 miles on it, and had sat for eight months in a back yard until the owner decided to revive it and put it back on the road. The only history the owner provided was that the vehicle ran badly, and that he didn’t have the money at the time to fix it. You know these customers all too well. These are the people who come to your shop claiming that they’re financially strapped and don’t want to spend a lot of money to fix their cars. Better yet, they feed you that famous line, “Just do it as cheaply as you can because I’ll be getting rid 42 MasterTechnician Online | www.mastertechmag.com

of it soon.” Meanwhile, they keep on using the same vehicle for the next decade or so. The biggest problems with cars that sit so long are that the gas in the fuel tank goes stale, and the invitation to little critters to feast upon wiring harnesses. So, whatever issues a vehicle had before it went into hibernation

Figure 1: 2001 Chevrolette pickup with a no-start 4.3L Vortec engine.

Posted to mastertechmag.com April 15, 2010 Key Word: Pea Pod

can only be compounded by sitting. This one started, but ran poorly prior to its storage period, but now it was in a crank, but no-start mode. The garage had already performed the basics by charging the battery, checking the fuel content, and changing the fuel filter. The spark plugs were soaked with gas from the customerâ&#x20AC;&#x2122;s attempt to start the engine, so the shop installed new ones. They only got soaked with fuel again within only a few cranks. The plugs were pulled again, and this time the tech performed a full compression test an all the cylinders. The results showed well above 150 psi. Next was a check of proper spark reserve using an ST125 tester. This stresses the ignition coil and forces it to put out close to 30 kVs. When the spark checked okay, the shop went one further step to ensure that the exhaust was not clogged. This was done by simply dropping the exhaust. At this point, nothing had panned out, so the shop decided to call me in to get a second opinion. When I arrived, I talked to the shop owner to get a little history on the vehicle and a description of what tests had been performed. I decided to do a simple scan (Figures 2&3) to make sure all the PCMâ&#x20AC;&#x2122;s vital signs were in order. There were no codes in the

system, and the data PIDs seemed to all be within range. Looking for codes and reading raw data such as coolant temp, air temp, TPS, or MAP can save a lot of time when dealing with an over-fueling engine, but sometimes you need to take a step back and look at the big picture. If the engine cranks and floods with raw fuel, it may not be due to a rich condition. It may be a lack of combustion created by valve timing, ignition timing, clogged exhaust, or even weak spark. The quickest way for me to validate most of these possibilities was simply to place a pressure transducer in any cylinder and use an inductive clamp to tag the spark plug wire of that same cylinder while itâ&#x20AC;&#x2122;s hooked up to a spark tester. I chose to capture the events in cylinder #1 (Figure 4) using my scope program coupled with my pressure transducer and inductive probe. You first need to be aware that each large purple curser represents 180 degree increments, and the smaller cursers represent 30 degree increments. The peak rise is the compression stroke, and the peak-to-peak rise is one full cylinder event of 720 degrees of crankshaft rotation. The small upward slope after the peak compression fall is the point at which the exhaust valve begins to open. I usually find this to April 2010 | MasterTechnician Online

2 Peas in a Pod

Figure 2 (Above) & Figure 3 (Below): A simple scan to make sure all the PCMâ&#x20AC;&#x2122;s vital signs were in order.

44 MasterTechnician Online | www.mastertechmag.com

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April 2010 | MasterTechnician Online

2 Peas in a Pod be about 30-45 degrees before BDC of the power stroke while cranking the engine. The waveform capture (Figure 4) shows the exhaust valve opening at about 30 before BDC of the power stroke, which proved that the timing chain on this high-mileage engine had not jumped, and that the crank-to-cam gear correlation was correct. If you look at the green square waveform pattern created by the inductive clamp, you can determine the time the spark occurred in the cylinder. There are other smaller green spikes, but these are usually caused by electrical noise the probe can pick up from other cylinders

firing. The first rise in the square wave is the point where spark has occurred. By looking at the pattern, you can see that the spark was very late by firing about 255 degrees after TDC of the compression stroke. This engine was not out in valve timing, but had a serious spark timing issue. Spark timing malfunctions can be caused by a crank sensor or cam sensor correlation problem from outof-synch trigger wheels, or possibly an incorrectly indexed distributor. The engine did run poorly before it was stored and finally cut out, so maybe the distributor gear was wiped. I set

Figure 4: The events captured in cylinder #1 using my scope program coupled with my pressure transducer and inductive probe. 46 MasterTechnician Online | www.mastertechmag.com

April 2010 | MasterTechnician Online

2 Peas in a Pod the crankshaft at TDC compression for #1 cylinder, and removed the distributor cap to check for proper rotor indexing, but was taken aback by what I saw. The distributor rotor was no longer secured to the distributor shaft because both screws were missing (Figure 5). The amazing thing was that it still spun when the engine cranked over, thus providing a good repetitive spark at the plug, but at the wrong time. Any technician checking the spark could have easily been fooled into thinking the spark was okay, but without the proper equipment it would be impossible to know just when the spark was actually occurring in the cylinder. Further inspection revealed the two missing screws to be lying under the rotor tucked away like two peas in a pod (Figure 6). It was as if they longed to be together in the face of doom when they both decided to jump ship together. What was amazing to me was how I quickly found this problem by simply using a pressure transducer and an inductive probe. Who would ever have thought 10 years back that there would come a time when I could actually see events occurring within a cylinder by simply looking at pressure readings on a screen. It’s well worth it to keep reinvesting in your business 48 MasterTechnician Online | www.mastertechmag.com

to keep up with the never-ending advances in technology. If there’s a piece of equipment out there that’s going to make my job easier, then I just have to have it. Getting to the root of a problem without wasting time and money on unwanted parts and labor is my idea of running a productive automotive business in today’s world of sophisticated cars. I hope this story can excite you to take yourself to the next level.

Figure 5: The distributor rotor was no longer secured to the distributor shaft because both screws were missing.

Figure 6: The two missing screws were lying under the rotor tucked away like two peas in a pod.

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Security Issues by Kerry Jonsson

ouston, we have a problem: A 2003 Chevy Venture that does not always start. It doesn’t even crank. I know what you’re thinking, “In the old days . . .” In the old days you also got five to 10 mpg with any car that had brisk performance. Electronics have changed everything. Most of you already know the tests you are going to perform for a nocrank situation. Some of them are obvious. Do you have proper battery voltage? Do the dash lights come on with the ignition key? Do you have juice on the large cable down at the starter? These are the basics. 50 MasterTechnician Online | www.mastertechmag.com

From there it get’s slightly more interesting. Do you have battery voltage out of the starter contact of the ignition switch? Is it a manual or automatic transmission? Does the voltage for the S terminal of the starter pass through a clutch switch or a park/neutral switch? And our personal favorite, “Did anyone install an alarm system 10 years ago about which we can have no idea of how it was wired, or if the company is even still in business anymore?” Barring any outside influences, we’ll just say this is a straightforward nopcrank situation. Also, each of the tests just mentioned still have to be performed, but the problems will

Posted to mastertechmag.com April 29, 2010 Key Word: Security

technology are coming out all the time. We need to keep up to speed with what is happening, even on sixyear-old vehicles.

Very often, the first part that gets replaced is the Passkey III module, even if it is not the problem. This sends the ignition key confirmation signal through the Class 2 serial data line to the IPC and the PCM.

start when you look at the wiring diagram. This particular vehicle has the Passkey III immobilizer system. So, if anyone wants to start a six-yearold minivan, they’re going to have to get past Passkey III first, even if it’s the vehicle’s owner!

First Things First Before you can start your diagnostic procedure, there is one important factor that you cannot overlook. You need to know how the system works. If you do not, you will perform certain tests and probably come up with more questions than answers. This is why training and studying are so important. New systems and new

So, how does the Passkey III system work? This is a true transponder type immobilizer system. In previous years, GM used several different types. Older systems have a resistor pellet in the key. This resistance is read by a Passkey/VATS module, and the engine is allowed to crank and run. The next generation uses a pair of Hall-effect sensors in the ignition switch assembly that tell the immobilizer software (within the Instrument Panel Cluster or Passlock module) that it’s okay to start and run the vehicle. This is known as the Passlock system, which was used until about the 2000 model year. In about 2001, the Passkey III system was introduced. It’s simpler than previous systems. You would think this would make it easier to diagnose -- there are only four components. There is the transponder chip in the key, the Passkey III module, the Instrument Panel Cluster (IPC), and the Powertrain Control Module (PCM). The Passkey III module is an antenna and immobilizer module mounted in one unit. It sends out a April 2010 | MasterTechnician Online

S e curity Issues

You need to know where the anti-theft control unit is and if it is communicating with the rest of the car. In this case, it’s in the IPC, and we have a code for lost communication with the IPC. You should start here.

signal that excites the transponder in the key. It then interprets the transponder signal from the key to determine if it is the correct key. Finally, it sends out the confirmation signal on the Class 2 serial data bus to the IPC and the PCM. This should allow the engine to crank and run. This vehicle is not cranking. Looking at the wiring diagram shows that there is no Park/Neutral switch to test. The ignition switch sends a battery voltage crank signal to a PCM/ Crank fuse in the instrument panel fuse box. The voltage signal passes 52 MasterTechnician Online | www.mastertechmag.com

through the fuse into the PCM. If the PCM wants the engine to crank, it will ground the starter relay. This energizes the relay and allows battery voltage to the starter “S” terminal. So, the PCM is in total control cranking the vehicle. Why is this? If the PCM does not like one of the inputs, it will not operate the starter relay. The transmission Internal Mode Switch (IMS) tells the PCM that the vehicle is in park or neutral to allow the vehicle to crank. Without the proper signal the vehicle may not crank, so check the IMS. What else can cause a no-crank situation?

April 2010 | MasterTechnician Online

S e curity Issues

A second code tells us the IPC is not powered up properly and therefore will not start Class 2 serial communication with the other control units. Since the PCM does not see an ignition key confirmation signal, it will not allow the engine to crank.

The immobilizer system will not only prevent the engine from starting, it can also prevent cranking. A series of inputs to the PCM will let the module know if it is okay to crank and start the vehicle. As mentioned earlier, one of these inputs is the anti-theft signal from the Passkey III module. Without this input, the vehicle will not crank. This immobilizer authorization is also sent to the IPC. The IPC then decides what to do with the Security light. Generally, when the light is on solid there is a fault in the system and the start is being blocked. You should be able to retrieve a DTC to determine where the fault is. You can start your diagnosis from there. If the Security light is blinking, it means the Passkey III module cannot identify the transponder signal from the key and it feels this is an attempted theft. The two different situations may 54 MasterTechnician Online | www.mastertechmag.com

call for slightly different diagnostics. A GM Tech II gives you the best shot at properly diagnosing the vehicle. You can access the PCM and look for anti-theft system codes. These codes are usually in the P16XX range. You can also communicate with the Passkey III module and see if the key is being read. Without a Tech II, it will be difficult to properly diagnose this vehicle, but letâ&#x20AC;&#x2122;s see what else we can look at.

Outside The Box Before you give up because you do not have a GM Tech II, or you do and the Passkey module says everything is okay, there are other places you can look to see if you have a problem you can solve. Since all involved control units communicate on the Class 2 serial data line, you need to make sure there is communication.

If you can scan the IPC for data, you may see this PID for ignition-on voltage. Here, that IGN 1 voltage is missing with the key in the on position. You now need to look at a wiring diagram.

Any aftermarket scan tool with GMspecific software should tell you which modules are communicating and which are not. See if you can get into the BCM and look for B or U codes. If communicating with the instrument cluster is one of your choices, select that one as well. You should be looking for communication failure codes. These may indicate the Passkey module cannot “talk” to the IPC or PCM to inform them that the proper key has been installed. In this case, you’re in luck. One of the codes retrieved in the instrument cluster is a B1440, and in the BCM a U1096 is set. Looking at these code definitions, you see the B1440 “Power Mode Master Input Circuits Mismatch” and U1096 “Lost Communication with Driver

Information & Display Control (IPC) systems.” These two codes direct you towards the instrument cluster. The U1096 tells you the BCM could not communicate with the IPC at some point. This is important to your diagnosis. The IPC contains the Passkey III control unit. If the anti-theft control unit/IPC cannot communicate with the rest of the vehicle, the start-authorization signal will never be sent to the PCM. The PCM will then shut down cranking. If you are able to access the IPC with your scan tool, that means the Class 2 serial data line must be up and operational, so it’s probably not a broken wire unless this is an intermittent connection. You now know at some point the IPC was not talking to the BCM.

April 2010 | MasterTechnician Online

S e curity Issues The other code is the B1440, which tells you one or more of the ignition switch power-on circuits has not made it to the cluster. Class 2 serial communication will not start if the IPC detects a problem with the ignition power-on circuits. You will need to look at the wiring to determine which wire at the IPC is not powering up. First, accessory power must show up followed by the ignition-on power supply. If the vehicle were being stolen or tampered with, the PCM would not allow the vehicle to crank without the confirmation signal from the IPC. The IPC would not send this signal if it is not powered up properly by the ignition switch.

You can confirm this quickly with a scan tool capable of getting data from the IPC. Looking at the instrument cluster wiring, you can see that there are two pink wires that feed supply voltage from the ignition switch. These power supply inputs pass through fuses, so that would be the easiest place to access them. You can also remove the cluster and look at the back of the connector for the two pink wires that power up the cluster. In this case, you find out one fuse is blown. It’s the fuse for the ignition switch (IGN 1) power output to the IPC. The fuse blows intermittently, so you have to find out where the short is in the wiring. Once you replace

This wiring diagram shows that the IPC has four power inputs. One is hot all the time, and three pass through the ignition switch. The pink wire (IGN 1) voltage goes to terminal “J” in the IPC connector. You can check the fuse (Courtesy of Alldata Information Systems). 56 MasterTechnician Online | www.mastertechmag.com

April 2010 | MasterTechnician Online

S e curity Issues the fuse, the engine should crank, but it may also start and stall. This is another symptom of the Passkey III being in theft mode. You are going to have to correct this theft mode problem before you can consider the vehicle fixed. You now have to perform the key relearn procedure. This involves attempting to crank the vehicle and leaving the key on for 10 minutes. You will need to shut the key off and repeat the process up to three times for the key to be learned to the Passkey III module. It would be a good idea to connect either a booster pack,

Here’s the connector at the back of the instrument cluster. Notice the one yellow wire that supplies the accessory-on and the two pink wires that supply the ignition-on power supply to the cluster. If the IPC likes the three power inputs, it starts communication with all the other control units, including the PCM. 58 MasterTechnician Online | www.mastertechmag.com

or battery charger at a low power setting to prevent the battery from going dead. If you have a Tech II and TIS2000 reprogramming software, you can perform a 10-minute learn procedure.

In Closing Although it is helpful to have the factory scan tool to quickly check for codes and look at data, you can do just as well by looking at a wiring diagram and having a little knowledge on how the system works. Knowing the Passkey III module is in the IPC and the IPC was not being properly powered up lead us to the correct diagnosis. In the end, we only checked for codes, scanned data and found a blown fuse. Of course, we did have to look for a short and that can be time-consuming. You must admit you typically don’t check the IPC power supply fuses in a nocrank situation. You also might say, “I always start with checking for blown fuses!” but with power distribution boxes being under the hood, under the dash, under the rear seat, and possibly in the trunk that’s a lot of fuses that will need to be checked. With anti-theft systems being what they are, you now have to look a little deeper when it comes to “no-crank/ no-start” situations.

April 2010 | MasterTechnician Online

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Inside the Insider Five Ways to Limit Liability 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. (Turn to page 1)

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

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Sole Proprietorship It 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 Matrix Businesses 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 Advantage One of the most powerful influences on choosing a repair facility is word-ofmouth recommendations from family, friends, and neighbors. Existing customers usually recommend a business based on trust and positive past experience. (Turn to page 10)

60 MasterTechnician Online | www.mastertechmag.com

Volume 1 | Issue 1

Five Ways to Limit Liability For Business Owners

By David V. Allen, Esq.

y 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

Human Potential

Using What You’ve Got

by Greg McConiga

he 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? Continue p.5: Potential