Hidden Wiring Problems Cause Lights And Codes

By Dan Frazier, Diagnostician

frazier-danDan has been in the automotive industry for over thirty years and is an ASE Certified Master Technician. Dan has a college background in electronics engineering and specializes in diagnostics and computer controls for Certified Transmission.

We all have routines. We live, eat, sleep, play and work by them. They help us get things done faster and more efficiently. Sometimes they are the fabric that holds us together, sometimes not so much. Anyone that’s been around this profession for any amount of time probably knows that the next ticket in the queue has a good chance of being anything but a routine repair.

Such was the case with a 2005 Dodge Dakota that rolled in to our shop equipped with 4WD, 4.7L engine, and a 545RFE transmission. Trucks like these are our bread and butter being located on the border of a big city with lots of farming and commercial operations on the other side. The customer’s complaint was “It feels like it’s slipping once in a while.” We have a routine for our initial evaluation like everyone else: check fluid levels, scan for codes, test drive, and perform an undercar inspection. While checking fluid levels I noticed this: A new/reman PCM (figure 1). Possibly not that it is relevant at this point, but something to make note of.

184a

Another of our routines starts at the counter when the service advisor is getting information from the customer. We ask a specific question: have you had any other work done on your vehicle in the last year? You may or may not be surprised at the answers you will get. Our front office staff is pretty good about prying information out of the customer, but a lot of times the information that the customer provides is grossly inaccurate and that can make a difference between having an accurate concern identified on the repair order or what I like to call a, “search warrant”. This customer had stated that he had not had any repairs done recently, so let’s move on with our initial inspection.

Fluid levels are good and the transmission fluid looks pretty fresh. Almost too fresh for 178K on the clock, and there are multiple codes stored in several modules. O2 heater B1S1 sensor, no closed loop operation, SKIM key code not stored, and on the transmission side we have a P0869 line pressure high, P0988 4C pressure switch rationality, and P0888, transmission relay always off. There were also codes stored in the airbag and ABS modules for lost communication with the PCM.

Moving on with the road test, things seemed pretty normal. The transmission shifted ok until a few minutes in. I usually record a data capture while test driving, but before I knew it the vehicle went into limp mode and the scanner had lost communication. At that time I still had communication between all the other modules except for the PCM. Cycling the key seemed to restore normal operation, so I decided to clear all the codes and start from scratch. It didn’t take long for the PCM to start acting up again. After a short test drive it went into limp mode and the P0888 (transmission relay always off) returned as a pending code. At that same time I also lost communication with the PCM on my scan tool and it also reset the lost communication codes for the CAN C bus in the ABS and airbag modules.

At this point I knew I needed some diagnostic time to figure out what was going on. After getting additional diagnostic time approved it was time to decide where I wanted to go with this. Did the loss of communication cause limp mode and the P0888, or did the egg come before the chicken?

If the PCM has a problem with communication I’m going to verify the basics: powers, grounds, data lines, and then make a determination based on what I find. If I find some new parts installed on a vehicle I always start with the installation of the parts involved. I accessed the new PCM and lo and behold, what did I find? (figure 2)

184b

See that connector on the right that is not fully seated? Notice that the connector locks for the other connectors aren’t locked either. The loose connector on this configuration is C1; a pretty important connector on Chrysler systems. Guess what it supplies to the PCM? Data lines? Check. Most of the power and grounds? Check.

I seated the connector and heard that “click” that we all like to hear when we connect something and re-checked my work. No such luck, but I thought I’d get lucky and earn my hour or so of diagnostic time but now I have to get the brain cells out.

At this point I’m concerned about the functionality of the PCM. With the loss of communication resulting in limp mode, coupled with the loss of communication codes stored in the ABS and airbag modules tells me we needed to check the basic functions of the PCM. Looking at the schematic for the CAN C lines, the only modules on that circuit are the PCM, ABS, and airbag modules that communicate to the scanner via the TIPM. On a lot of vehicles, you can scope the CAN lines straight from the DLC pins 6 and 14, however on this common Chrysler setup pins 6 and 14 only communicate with the TIPM. The CAN signals from there are transmitted to the other modules on the CAN C network. (figure 3)

Figure 3

I decided that I needed to verify the CAN networks ability to transmit and receive messages as well as verifying the correct powers and grounds that will let the PCM function as designed. The easiest thing to do (I like easy) was to scope the CAN signals at a couple of modules to verify there is a signal present. I hooked up my lab scope to the CAN+ and CAN at the PCM and ABS modules to compare signals. (figure 4).

184d

We can see that the CAN HI signal is being pulled from 3.5v to 2.5v, CAN LOW is pulled up from 1.5v to 2.5v. The top capture was taken at the PCM; the bottom capture was taken at the ABS module. The signals indicate that the CAN network is intact, and there are no discrepancies in the waveform. From there, I verified correct voltage supply to the PCM, and all grounds voltage dropped at less than 5mv, which is actually pretty good for a 13 yr old vehicle. These readings were all taken while the condition was occurring, leading me to believe that this PCM had internal issues.

A remanufactured PCM was ordered from a fairly reputable supplier that we’ve used in the past. After installing the new PCM, the engine had a definite misfire and set a P2313 – insufficient coil burn time on cyl #8. Yep, the new PCM had a bad coil driver for that cylinder. It ran fine with the original PCM, so we got another one on the way. I’m very hesitant to install used or reman PCMs (especially on Chrysler products) because I’ve seen way too many issues that have resulted in a new problem after the PCM is replaced.

After replacing the PCM once again, the engine ran like a champ, the transmission shifted great, and test drove a few times for about an hour total and no transmission codes had set. The O2 sensor code returned, but the customer is kind of a DIY guy and said he would take care of it himself.

Fortunately, this diagnosis was fairly easy. Being able to reproduce the issue along with an understanding of how the system works and a logical diagnostic path to follow helped a lot, not to mention that the components in question were easily accessible. This one is out the door and now it is time to move on to the next routine diagnosis.

Hidden Wiring Problems Cause Lights And Codes

By Troy Hopp, Diagnostician

hopp-troy

Troy has been in the automotive repair industry his entire career and has been with Certified Transmission since February 2010. He has an Applied Science Degree in Automotive Technology from Western Iowa Tech and is an ASE Master Certified Technician.

 

About two months ago a customer brought in his 2006 Ford E350 Econoline van equipped with a 5.4L engine and a 4R75E transmission for an evaluation. His concern was that the check engine light was on and the transmission seemed to shift hard at times. We always begin our evaluation with a battery and charging system test with a Midtronics electrical system analyzer, and we scan all modules for codes using a Snap-On Verus Pro if we are not using an OE scan tool. After a quick visual inspection of the vehicle and checking the engine oil level, we will proceed with the road-test.

After scanning the PCM, I pulled two codes that were stored: P0740 (Torque Converter Clutch fault) and P0743 (Torque Converter Clutch System Electrical fault). The fluid level was correct, but it was dark red in color with a slightly varnished smell. My next step was to clear the codes and try to duplicate the customer’s concern. After driving the van about 5 minutes, the torque converter clutch started to shudder and I could see on the scan tool that the torque converter clutch was slipping. P0740 and P0743 both reset and the transmission began to shift hard because it went into limp in mode. At this point I was fairly confident that the problem was a slipping torque converter clutch, but to be absolutely sure I obtained the customer’s permission to perform a visual pan inspection. A quick removal of the pan revealed a large amount of metal and clutch debris confirming an internal transmission failure.

After explaining the course of repair to the customer and obtaining repair authorization, we replaced the defective transmission with our remanufactured unit. All of our transmission installations include hot-flushing the oil coolers to ensure complete debris removal from the entire system. We also reprogram the powertrain and/or transmission control modules to the latest calibration for optimal operation. While the transmission is removed we also thoroughly inspect the flex plate, rear main seal, engine mounts, transmission mounts, u-joints and/or CV joints to ensure everything is in good working order and replace them if needed, then complete the installation of our remanufactured transmission.

With the installation completed and all of the updates performed, it was time for a final road-test to make sure the customer’s concerns were all alleviated. The 25-minute road-test verified that the torque converter clutch no longer shuddered or slipped and the transmission shifted and operated perfectly. However, after getting the van back to the shop, a quick scan of the codes revealed that the P0740 code was had not returned, but the P0743 code had. It was now apparent that the van had two different issues at play.

I cleared the code once again and went for another road-test, but this time I had another technician with me to monitor the scan tool for PCM commands while I drove the vehicle. For the first several minutes everything was working just fine, but the converter clutch seemed to apply earlier than it had on the previous road-test, so I asked the tech if the TCC was commanded on. He stated that it was not, so it seemed we were getting our scope narrowed down to an electrical issue. A quick scan for codes showed that the P0743 had returned so then we returned to the shop.

At this point I was comfortable to assume that the P0743 code was most likely caused by an external wiring problem, or possibly by the PCM itself. Since the torque converter clutch was apparently being commanded on and off by the PCM properly, the PCM was not my first suspect. I felt it was safe to assume the PCM was ok based (in part) of the fact that we rarely have to replace a PCM in a Ford application, so I first decided to direct my attention to the wiring harness and connectors.

After a close visual inspection of the connectors at the transmission and at the PCM, I verified that they were clean and the terminals were tight and making good contact. When I back-probed the TCC solenoid control wire at the PCM with KOEO, I had full battery voltage and the circuit seemed to ohm out fine, but something had to be amiss that these tests did not reveal. I decided it was time to inspect the wiring harness, but of course no problems were found where the harness was easily accessible. Removal of the engine cover (dog house) was required for a complete inspection of the wiring harness.

Once the engine cover was removed it was revealed that the harness was lying against the EGR tube and had melted through the harness conduit and into the insulation on the torque converter clutch solenoid wire, thus causing it to ground out through the EGR tube and setting the P0743 code.

I cannot completely explain the intermittent nature of this issue or why it would just act up when it was hot, but can theorize that the EGR tube only made enough contact with the wire when there was some heat expansion of the pipe, or just from some movement while driving. (Figure 1)

figure1

Figure 1

I repaired the shorted wire, replaced the conduit where it was melted and properly secured the harness away from the EGR tube. Now it was time to reinstall the engine cover and take the van out for another final road-test. I drove the van for 30 minutes and the transmission shifted and operated ok, the check engine light stayed off, and no codes were reset. Now both of the codes were repaired, the customer picked up his van and was on his way.

 

 

 

 

Beware Of Component Variations For High-Performance Transmissions

By Allen Channel, Diagnostician

author32Allen grew up under the wings of his father. He worked in his father’s shop starting out washing parts and cleaning. He soon was working on cars, but more specifically, transmissions. He eventually took over the business and ran it for many years. He later went to work for a Chevrolet dealership performing most of the transmission repairs. He left his native state of Ohio and joined Certified Transmission in May, 2015. He is currently our diagnostician in our Blue Springs, MO location. 

 

In addition to the OEM-spec remanufactured transmissions we build, we also offer a series of heavy-duty transmissions available in three different stages. The subject of this article is in regard to the installation of our Road Ripper™ 3000 (stage 3 unit) in a 2005 Dodge 2500 Pickup equipped with a 5.9L diesel and a 618/48RE transmission. The vehicle had been in use for about a month when the customer returned with an issue that the transmission was stuck in gear and would not shift. We did not want any damage to occur by the customer driving the vehicle to our location, so we set up a tow to have the vehicle picked up.

During my initial evaluation, everything appeared to be normal. Prior to the road test I hooked up the scan tool so I could scan all the modules, and to my surprise there were no diagnostic trouble codes stored. at this point a road test was in order, and as I prepared the scan tool for monitoring I looked at the data menu and noticed the governor pressure was at 98.4 psi with the key on engine off (KOEO), and the transmission throttle valve actuator (TTVA) was at 99%.

This data appeared to indicate an issue with the electronic governor pressure system, so I installed a pressure gauge to the governor port and the indicated pressure was at 0 psi as opposed to the nearly 100psi that the scan tool showed. I test drove the truck and the governor pressure did not come off 0 psi regardless of speed (at least the speed I could get to when it is not shifting). Although the scanner shows 98.4 psi all the time and TTVA is always 99%, the transmission is in a default mode and the transmission won?t shift out of 1st gear. After a short test drive I rechecked for codes and none were found.

The reason there were no codes is because electronically the system was within correct parameters and I did not drive it far or long enough for it to set the P1762 governor pressure offset code. With this information we could conclude that the sensor was not giving us accurate information as originally suspected, but when I looked at the transmission temperature it was working correctly which told me the ground was intact for the sensor (Fig 1), since the pressure sensor and temperature sensor share a common ground. I checked the 5 volt reference at pin 2 (yellow & pink wire) and the voltage was correct. I then checked the sensor signal wire at pin 4 (yellow & brown) wire, and it read 4.75 volts which is very near reference voltage (Fig 2). The correct reading should be about 0.7 volts KOEO. The pressure sensor works similar to a throttle position sensor, except it uses fluid pressure to change its voltage output instead of a mechanical device.

Figure 1

182a

Figure 2

182a

At this time I determined we would need to check the components inside the pan. When I pulled the pan everything looked good and nothing abnormal was found. I did a visual inspection of the internal wiring and everything looked in order. We keep the sensors in stock at the store, so as a quick test, I plugged a new sensor in and the scanner immediately showed 0 psi for governor and the TTVA went to 0%. I plugged the old sensor back in and reading went back to 98.4 on governor and 99% TTVA. I was able to see a change for the better and then to verify the part I was replacing was definitely faulty.

I replaced the governor sensor, installed the pan and went for a road test. The governor pressure was now correct and transmission is shifting great again. Problem solved, or so I thought. Remember when I said earlier this is a Road Ripper™ 3000? Whenever there is a warranty issue, we submit a claim to our warranty department which reviews the concern and makes the recommendation for repair. Our warranty technician reviewed the repair and sent a message back stating since this is a Road Ripper™ 3000 unit, and therefore requires a special high-pressure sensor. The OE-style pressure sensor would work, but eventually the diaphragm will not survive with the higher pressures the Road Ripper™ 3000 is set up with.

We ordered a high pressure sensor from Rostra, and once the sensor arrived I realized how to tell a high-pressure sensor from a stock (OE) sensor. The stock sensor is all black, but the high-pressure version has a white cover on it (Figs 3&4).

Figure 3

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Figure 4

182d

Had we installed the OE-style sensor, the transmission would have worked for a while, but for how long is hard to tell. Thanks to our knowledgeable technical department, they were able to let us know about the discrepancy before we delivered the vehicle to the customer and had a potential governor issue down the road. This is another example of a system of checks and balances to ensure a positive customer experience, and when several people are involved there is a better chance something won’t be overlooked.

The repairs were completed, pressure testing and road testing were completed, and the vehicle was ready to be returned to the customer with the confidence that we had fixed it right, the first time.

The takeaway from this experience highlights the need to identify any special circumstances that may impact the overall quality of repair. While the diagnosis was routine and basic, overlooking the fact that this high-performance unit used a non-OEM spec part could have created a comeback situation down the road. An effective check-and-balance system saved the day on this one, and will again for a future day.

New Ford Programming Procedures

By Chris Adams, Diagnostician

adams-chris-2Chris Adams started with Certified Transmission in 1986 as an R&R technician, and currently works as our Diagnostic Trainer. His current duties involve training and advising our retail diagnosticians, as well as assisting in the research and development of our remanufactured products. He also holds ASE Master and L1 certifications.

For those of you that perform J2534 programming, you may have noticed that there have not been any updates to the Ford Module Programming (FMP) since the last release of FMP 105. Although it had remained functional as long as your subscription was current (or at least up until the writing of this), it won’t be long before you will have to start using the new software which is labeled as FJDS (Ford J2534 Diagnostic Software).

The following statement is taken from the Motorcraft Service website:

“Ford J2534 Diagnostic Software (FJDS) – The factory Ford Motor Company vehicle diagnostic tool designed for use with J2534 compatible Vehicle Communications Interfaces (VCI). FJDS software provides module reprogramming software (FMP) that covers 1996 to present Ford, Lincoln, mercury module programming functions plus complete dealership level vehicle diagnostic software for all 2018 to present Ford and Lincoln vehicles.

FJDS is a flexible diagnostic tool that utilizes standard computing platforms to work with Ford’s VCM II or J2534 compatible devices. The FJDS software license includes time-based access to the FJDS software, software updates and calibration files.”

The FJDS R108.1 was released on 12/06/2017, and according to the future release schedule, there will be an update approximately every two weeks with the next release scheduled for 01/04/2018, then 01/17/2018 and so on. It will switch to version 109 sometime in March. The functionality of FJDS compared to FMP are very similar; in fact, folks that don’t use it every day will probably not really notice a difference.

FIG 1

Figure 1

Don’t get the FDRS and FJRS mixed up as the FDRS (Ford Diagnosis and Repair System) is the replacement for the Ford IDS tool for the 2018 and up MY Vehicles and is designed to work with the VCMII interface.

The release of the FJDS brings Ford into compliance with the RTR (Right To Repair) act that requires OEMs to provide software-based OE-level diagnostics and repair information as of Jan 1st 2018. It appears that Ford is just covering the 2018 and up MY vehicles with the OE diagnostics and only programming services are available for anything older than that. Maybe Ford will expand on the coverage for diagnostics, but I am not holding my breath.

A few other things have changed, too: PC system requirements have been updated to a minimum spec of an Intel I5 or I7 processor speed of 1.8Ghz to 2.1Ghz (depending on which operating system you are running), 4GB of RAM if using Windows 8.1 or Windows 10 (yes, it is Windows 10 compatible), and Internet Explorer version IE11. The recommended specs are higher, and all of this info can be found at www.motorcraftservice.com and then click on the “Diagnostic tool support” tab.

To get started, select the “Reprogramming” tab on the Motorcraft service website, and when selecting the FJDS or FDRS button, you will be taken to another website where you will have to create a NEW account.

FIG 2

Figure 2

Your Motorcraft Service username and password is NOT valid in this environment so you must create your own by selecting “Create an account”. This is the website where you will pay for the subscriptions and get the licensing keys from. The Motorcraft service website (as far as FJDS is concerned) is just for downloading the software; they made it a little confusing from what it used to be. As with anything new, there will be a bit of a learning curve, but after all the initial stuff is set up, it is fairly painless.

The next thing that will affect some shops is the licensing protocols for FJDS. For those of you that use or have used the IDS System, the FJDS is structured the same way: anyone can download the FJDS software, but it is only functional with the software license that is provided with a paid subscription. 2 Day = $49.95, 30 Day = $149.95, or 365 Day = $849.95. Upon purchase of a software license, the user will receive a 20-digit licensing activation code (key). The user can then activate the key using the “Activate a license” feature in the software. Activating a key binds the key to the PC on which it is entered. Since the software license binds it to the PC and not the diagnostic hardware, a single software license can only be on one PC at a time.

Each laptop or PC running the FJDS will require its own license (or the transfer of a license) since each license binds it to the PC. FJDS software must also communicate with the license server on a regular basis to validate the license, and validation automatically occurs at each start-up of the software when the PC is connected to the Internet. This is required at least every 29 days, and after 30 days with no validation the license will become “invalid” and the software functionality will be disabled. You can also validate in the software via a button in the “Information” tab.

FIG 3

Figure 3

Updating the software is simplified and faster than it was with FMP, and you no longer have to uninstall the old software. You simply log into your subscription, download the new software and install it. You will get an update screen that pops up when a new version is released, very similar to how the IDS system updates.

Just an FYI: all of our company’s retail locations have specific laptops that are used for programming only. They are HP Pro Books equipped with Intel I7 7th-generation processors equipped with 8GB of RAM, and they run really well. The laptops are set up with a “dual boot” which is similar to a “partitioned” drive, but they actually have two separate operating systems installed. Between the two sides we have programming software for GM, Ford, Chrysler, Mazda, Honda, Hyundai, Kia, Nissan, BMW, Subaru and Toyota and everything works well. The laptops run smoothly and we have been running like this for almost two years.

Having the proper resources and equipment for programming vehicles is a must for any modern shop. As technology advances and becomes more complicated, your need for updated software and hardware becomes paramount. Charge appropriately for programming services, and become the “go-to” shop for performing wholesale programming for other shops that lack the capability. Done correctly, this can become a nice profit center for your shop and keeps your techs busy.

Incompatible Programming Must Be Addressed When Installing Used Components

By Chris Adams, Diagnostician

adams-chris-2Chris Adams started with Certified Transmission in 1986 as an R&R technician, and currently works as our Diagnostic Trainer. His current duties involve training and advising our retail diagnosticians, as well as assisting in the research and development of our remanufactured products. He is also holds ASE Master and L1 certifications.

We had a local general repair shop bring us a 2014 Jeep Grand Cherokee 3.6L V-6 engine equipped with a ZF 8 Speed (845RE) transmission; they had just installed a “rebuilt” transmission that was sourced from a salvage yard. The customer’s stated concern was, “The place that built the transmission just said it needed to be programmed.” Needless to say, we knew that this was going to be an adventure.

When we began our evaluation, we found that there were a bunch of ‘U’ codes for invalid data received from the TCM, but we did not get that far into it since the customer was adamant that they just wanted it programmed and did not want us to do any kind of diagnostic. After all, it was a “rebuilt” transmission, so what could possibly be wrong? I wish I knew how to convey sarcasm in the written word; I can do it in person pretty well.

We do a lot of programming in our shops and we have equipment and software to cover almost all automobile manufacturers in-house, with the exception of a few higher-end European vehicles that we do not see on a daily basis. Each of our locations has a laptop that is specifically setup for programming plus a J2534 device, but we also have a variety of OE tools also. For this vehicle I grabbed the Witech tool and proceeded to go through the reprogramming process. There was an updated calibration available so I went ahead and flashed the TCM to the updated part # of 68234057AA, and everything went fine. Programming completed with no errors or warnings, or so I thought.

After programming, I always go back and clear codes from all modules and also look at the reports that WiTech will generate, but specifically the ECU data. This is where I saw some discrepancies. Figure 1 is the TCM data, and it is here that you can see that the current VIN and original VIN do not match. The one that ends in 2111 is the correct VIN for the vehicle.

FIG 1

Figure 1

Needing to know what this transmission came out of was my next step. Running a VIN decoder (Figure 2) showed that this unit was pulled from a 2015 RAM 1500 with a 5.7L engine.

FIG 2

Figure 2

What? Dealing with the 8 speeds is fairly new to us and we have not seen that many in our shops, but I was pretty certain that an 8HP70 that was behind a 5.7L V8 would not work properly in the place of a 845RE mated to a 3.6L V6. To try to make a long story short, the used, er…whoops, “REBUILT” transmission did have some work done to it, but they either installed a complete valve body or at least the TCM from another vehicle. While it is possible in certain circumstances that a used TCM can safely be installed in another vehicle, the calibration or ECU part # has to be for that same vehicle as neither the OE WiTech tool nor the J2534 programming software will allow you to change the calibration # or the VIN in the TCM. It will always have a current/original VIN mismatch when looking at ECU data, but when this is only in the TCM, it does not seem to set a code or cause any other issues (I must say that this is from very limited data, and might not be true in later model vehicles 16 & up; this example was a 2014 MY vehicle). Bottom line is that this would never work as-is.

The second part of this story starts after we installed a NEW complete valve body from FCA into this Jeep to make things match. Our WiTech was not available so I used the J2534 tool to program the new TCM. Here is where I want to direct your attention, because if you are not paying attention this is where you could get into some trouble. You probably can’t read the writing in red on that screenshot, so what it says in Figure 3 is this:

NOTICE: There is more than one flash to select from for this ECU. Ensure that you have selected the correct one in the drop down box before you initiate the flash. Note that the contents of the Service Bulletins table change according to the flash selected.

FIG 3

Figure 3

The “FLASH ECU” button can be pushed, but the 68225555AF calibration that is listed is NOT correct for this vehicle! You must select the correct file from the drop-down box, and the correct Cal file is shown in Figure 4 of 68225561AG in the topology view.

FIG 4

Figure 4

In the next set of images you will see screens that you would encounter during the programming process. Make sure you get all the way to “Flash Complete”, and the “OK” button is highlighted.

FIG 5

Figure 5

FIG 6

Figure 6

FIG 7

Figure 7

FIG 8

Figure 8

After you get done programming, as you see in Figure 9, the “FLASH ECU” button is still there.

FIG 9

Figure 9

Even after programming it takes a bit of time before that goes away. The VIN and the correct calibration are shown above it, but before programming the VIN was all question marks and asterisks in the part # line. When I clicked the topology view in Figure 10, the “Flash” button went away and the TCM displayed as “Current”.

FIG 10

Figure 10

I do want to add that this process is specific to the J2534 programming process; if you are using the OE WiTech tool, it will pull the correct calibration file by the VIN, and with the blank TCM part number, you will only have the one option. We can only hope that the aftermarket software can start working more like the OE software does as time goes forward, but for now we need to work cautiously when dealing with the 8, 9 and 10 speeds that will be coming in our doors.

You can look up the correct calibrations on the Tech Authority website without a subscription, but you have to know where to look. Here is the link:

https://kb.fcawitech.com/secure/chrysler-scan-tool-flash-availability-document-775.html

At the bottom of the TA homepage there is a link called “Related documents and links”. If you click on that, it will show several other links that you can get to without a charge, and one of them is the “Flash availability” PDF file.

It will be challenging in the coming years dealing with used components that have vehicle-specific programming within the modules inside of them. Since the salvage industry uses part numbering standards such as “Hollander”, it lumps incompatible software with compatible hardware. We must always ask questions about the origins of these components as that will help us determine how we can proceed to solve the customer’s vehicle problems.

Resistance Checks Don’t Tell The Whole Story

By Troy Hopp, Diagnostician

hopp-troyTroy has been in the automotive repair industry his entire career and has been with Certified Transmission since February 2010. He has an Applied Science Degree in Automotive Technology from Western Iowa Tech and is an ASE Master Certified Technician.

About a month ago a customer came into our shop with a 2008 Chrysler Town & Country equipped with a 4.0 liter V6 engine, and a 62TE transmission. He was complaining that it had a whining noise, and sometimes it would not shift and seemed to stay in the same gear. When the vehicle was hooked to the scan tool it had a code for the overdrive solenoid control circuit (P0760). The fluid was at the correct level and smelled like normal fluid, however, it was dark purple indicating possible metal contamination.

I took it on a test drive and verified that the whine noise was definitely coming from the transmission, but it shifted and operated ok. There were no other DTC’s in any other modules except for the TCM and the visual inspection did not reveal anything that needed attention. We also do a battery and charging system test with a Midtronics analyzer which also passed all the test protocols. The next step was to get the customer’s permission to remove the transmission pan for inspection, which the customer granted so we then proceeded with the inspection. Upon pan removal, severe fine metal contamination was verified on the bottom of the pan, along with large amounts of metal in the filter when it was cut open. I think we found the cause of the noise!

The customer decided that with 160,000 miles it was best to replace the entire transmission with one of our remanufactured units. We replaced his transmission, reprogrammed the powertrain control module, and used a “hot flush” machine to clean out all of the metal out of the transmission cooler and lines. I cleared the code and test drove the Town & Country for about 30 minutes with both highway and city driving. The whine was gone; it shifted perfectly and did not set any codes, so I felt that it was safe to presume the code was caused by a faulty overdrive solenoid.

We always inform our customers to return to the shop in 15 days to perform a free follow-up evaluation so we can make sure that there are no leaks, codes, or any other problems associated with our repair work. The customer returned about two weeks later stating that the transmission was nice and quiet now, but that it still got stuck in second gear one time since we replaced his transmission. I scanned the Town & Country to find that the same P0760 overdrive solenoid code was stored. So we then had to ask the customer to drop off his vehicle again so we can figure out what was causing the code to reset, we put him in a rental car so we could continue diagnosis. At this point I figured it was safe to assume the solenoid itself was not the problem since it was replaced with the transmission, therefore it could only be a bad overdrive solenoid control wire or an intermittent internal failure of the powertrain control module.

The powertrain control module never failed to activate the overdrive solenoid during the solenoid on/off testing with our scanner; therefore, I did not think the problem was with the driver in the powertrain control module. I then directed my attention towards the yellow and gray overdrive control wire from terminal #1 of the powertrain control module, to terminal #19 of the transmission solenoid connector (FIG 1).

FIG 1

Figure 1

Since I have been burned before by using resistance checks, we try to only use voltage drop testing unless the component is completely inoperative. I back-probed terminal #19 at the transmission solenoid connector in preparation for a voltage drop test. I had battery voltage until I activated the overdrive solenoid with the scanner, and 4 volts were indicated on my volt meter, indicating that the solenoid was only getting about 8 volts of the 12 volts needed to properly operate the solenoid, however it was apparently enough to get the job done most of the time. Was the voltage drop on the B+ side, or the control side of the circuit? I probed on pin 21 for the 2-4 solenoid, and when activated the DVOM showed about .10 volts indicating a good circuit which confirmed the integrity of the B+ side of the circuit.

A closer inspection of the wire revealed that only three or four strands of copper at the terminal of the transmission connector were making contact (FIG 2). A small tug on the wire was all it took to completely break it. This is a perfect example as to why a simple ohm check of the wire is not a good enough test in this case; an ohmmeter test would show normal resistance indicating no problems with the wire, even with only three strands of copper holding it together. The real issue was that the damaged wire could not support the amperage needed to properly activate the solenoid at times, especially when hot.

FIG 2

Figure 2

I did get a little lucky during diagnosis. I wanted to look at the connector just to make sure that the R&R technician had the connector fully locked into position, which it was. However, after checking the connector the problem went from being extremely intermittent to setting the code pretty easily, so that did narrow down my focus on where to look for the problem. Happy accidents can be helpful in cases like this.

I found a transmission solenoid connector pigtail that we use for testing and robbed one of the terminals/wires out of it, and installed it into the Town & Country’s solenoid connector. A quick voltage drop test showed that the solenoid was now getting use of all 12 volts being supplied to it. I cleared the code and test drove the van another 30 minutes and no codes were reset. We sent the customer on his way and he has not been back, now having both of his initial complaints resolved. The whine noise was easy to figure out, but the intermittent code P0760 in this case took a little extra effort to diagnose.

Now wouldn’t you know it, within one week of repairing the P0760 in the 2008 Town & Country, a 2010 Chrysler Town & Country, also equipped with a 4.0 liter V6 and a 62TE transmission, came to our shop with a complaint of a check engine light, intermittently not shifting, and staying in second gear. This vehicle’s transmission fluid level was full and in good condition, however. I scanned it to find a 2-4 or 2C solenoid control circuit code P0755. I thought, “What are the chances that this van had the same problem as the 2008 Town & Country I repaired a week ago?”

I decided another voltage drop test was in order. I back-probed the solenoid connector at terminal #21 dark blue and yellow wire for the 2-4 solenoid control. I activated the solenoid with the scanner, and my voltmeter read 5 volts indicating that the solenoid was only getting 7 of the 12 volts needed to make it properly operate. I barely tugged on the wire, and it snapped right off (FIG 3); it was the same exact scenario as the wire on the ‘08 Town & Country a week ago.

FIG 3

Figure 3

I replaced the terminal, cleared the code and test drove the van. It shifted fine and no codes were reset. Who says lightning can’t strike twice?

Improvise And Accept The Difficult Jobs

By Mike Greer, Diagnostician

greer-mikeMike has been with Certified Transmission since 1996, and been in the industry since 1987. He is an ASE master Technician and has served as a Master Builder for the company in the past.

My article is going to be a little different this time, and geared more toward the R&R technician. It’s about a car that came to us from a large local dealership that has 13 different locations, and works on 14 different makes of vehicles. The subject vehicle is a 2014 Mini Cooper Countryman AWD, with a 6 speed manual transmission. Mini is one of the only makes that this dealership does not sell; being in good standing with this dealership, they brought it to us to perform the repairs needed and get their customer back on the road. With very little information available on the internet for removal and installation, we did think about purchasing a short term subscription to BMW/Mini service information, but hey, it’s a clutch job, so how hard could it be?

The vehicle needed a clutch replacement which seemed fairly straight forward, so we jumped right in to get this back to the customer as quickly as we possibly could. We ended up needing to call the local Mini dealer and order OE parts since there was limited availability of aftermarket clutch parts. This vehicle was equipped with a Dual Mass Flywheel set up, so with this knowledge we started the removal process. Remove the air box, get the battery out of the way, removed the bell housing bolts, etc. all from the engine compartment, then raise the vehicle up to start taking off the front two wheels. Also, a good trick we found was taking the driver’s side headlight out, and removing the front bumper cover as this gave us better access to the transmission and it was removed fairly easily and quickly.  We felt that this added step saved us a lot of time not trying to fight getting access in such a tight area. After this, things started to get interesting.

This is a photo of the rear driveshaft where it attaches to the PTU.

Figure 1

Figure 1

We discovered a TSB that referred to this attachment. It told us we needed a special tool to get it apart and it is a large wrench end that attaches to a long half-inch extension to get it apart.

Figure 2

Figure 2

We obviously did not have anything even remotely close to this tool, nor did any of our other shops in the area. Calling the local dealer, we could buy the special tool, but it was a little over a week out to get one. Upon further investigation we decided the PTU possibly could come out with the driveshaft still attached.

After unbolting the PTU and separating it from the transmission we found the next road block: the intermediate shaft in the PTU is too long to get the PTU removed without it hitting the back of the engine. We started looking over how everything is put together, to see if we could still make this work. While looking, we found a snap ring around the passenger side axle.

Figure 3

Figure 3

With that snap ring removed (and with the help of a sharp, new pry bar, and hammer) the axle popped out of the PTU allowing us to remove that PTU with the driveshafts still attached. This might not be the easiest method, but it worked and we transmission technicians always seem to find a way to get ‘er done!

This is a picture of the PTU on the floor with the attached pieces mentioned.

Figure 4

Figure 4

After getting these parts out of the way, we could then remove the transmission. As a side note, if you do need to service the driveshaft of any reason, you will need that special tool I mentioned previously to get the driveshaft separated from the PTU. Back on track, everything else went very smoothly and we finished replacing the clutch, flywheel and all associated parts. We put the vehicle back together, and then went for that final test drive.

Some additional notes: make sure the correct parts are ordered for these vehicles, and the labor charge is sufficient. This was a very big clutch job, and very expensive as the total bill came out to be around $2700 retail. Make sure if it is supposed to have a Dual Mass Flywheel (DMF) it gets replaced. Trying to cut corners on a job like this does not do you or your customer any good. Not pricing this job out correctly up front can mean one of those phone calls that you do not want to make after the vehicle is disassembled; it can mean a very large pricing difference, as well as correct fitments.

This is where the LUK clutch catalog or online catalog can come in handy. With this catalog, you can check to see if they offer the DMF set up for your application. LUK offers a much more affordable option for your customers versus the OE parts (for many applications, LUK or Valeo are the OE supplier), so you will save your customer quite a bit of money if your application is available from them. In their catalog, you can also find the “flywheel options” if you are sending out the flywheel to be surfaced, as the information in the catalog will tell you if it is a flat, step, DMF (cannot be turned), or cupped style. It will give you dimensions and measurements so you can make sure the flywheel will still be in spec after having it surfaced.

In closing, I just want to say if you get one of these all-wheel drive Mini Coopers in your shop, do not turn it away for fear of being too complicated. The job ended up being fairly easy, the shop made good money, and the R&R technician made good time on it. Next time he will be able to do it even faster, and have an even better turnaround time.

Verify Data Before Condemning Components

By Dana Deeke, Diagnostician

deeke-danaDana joined with Certified Transmission in 1991. Dana has worked in all positions at the Lincoln location, starting as an R&R technician and is now our current diagnostician for our Lincoln, NE facility. He enjoys car racing and spending time with family and friends.

Every now and then we run across a vehicle that has a concern we have seen many times before and we almost automatically try and diagnose it by memory; it’s almost like a reflex we develop over time. Of course as we all know too well, this can lead you down the wrong path if you stray away from complete testing and verification.

The subject vehicle is a 1999 Chevrolet Tahoe. It came to us on a wrecker, as the customer was not comfortable driving it to us. The concern was stated as harsh shifts and a check engine light on. The vehicle was brought into the shop and the fluid level and condition were checked. The fluid level was full but had a strong burnt odor, and was discolored. A quick scan of the computer revealed code P1870, “transmission component slipping”. We now knew what was causing the check engine light and harsh upshift concern. From here I left the scan tool attached and went for a short road test to try to further verify the concern. Just as the code had indicated, the scan data showed the TCC turning on, the duty-cycle start to ramp on (eventually getting to full duty-cycle), and the TCC slip parameter still showed an abnormal level of slip.

At this point it appeared that the PCM was commanding the TCC on and the duty-cycle was increased in response to the slip that was sensed, however the RPM was not coming down as expected and the P1870 would then set. It appeared that we may have had some sort of mechanical failure of the torque converter clutch system. We do see that from time to time. This is where some more questions for the customer can help. Whenever possible, I like to try to find out the history of the vehicle I am working on, as it can lend clues to the failure. In this case, I was glad I was able to find out some good info.

This truck had had the transmission replaced not too long before it came into our shop. As we learned more from the customer, it became clear that there was a pattern present. By now you may have guessed that the previous failure also involved the P1870 code! It was time to look at this issue a little more closely.

I looked around through TSBs and found all the typical failures you see with this code. I also ran it past the guys in our technical division. They get calls from all kinds of shops and can be a great resource for information. Everything I looked at pointed to a mechanical failure, but I was starting to doubt this with the information I found out about the previous failure, and the same code being present. Could two transmissions have the same failure? Absolutely possible, but sure seemed unlikely.

I pulled up the wiring diagram and connector views for the PCM. The PCM is located on the driver’s side fender well so it is easily accessible (FIG 1).

FIG 1

Figure 1

I decided to try to verify that the on/off solenoid was working and being commanded to work. Both the TCC on/off solenoid and the TCC PWM solenoid are located on the valve body on this transmission and would require dropping the pan to access them, I decided to start my testing at the PCM (FIG 2 & 3). Connector C1 (blue) at the PCM contained the TCC on/off solenoid control on pin 10, which was a tan/black wire. C2 (red) contained the TCC PWM signal wire on pin 7, which was a brown wire (FIG 3). Checking from the PCM with a DMM I was able to verify that the signal was getting to the on/off solenoid, and that the solenoid was indeed turning on.

FIG 2

Figure 2

FIG 3

Figure 3

Next I ran the vehicle on the hoist while watching the TCC data. I have used this strategy before with gear ratio codes to see if they would reset on the hoist without the weight and load of the vehicle. The PCM scan data showed TCC solenoid turning on, and TCC PWM solenoid start to raise the duty-cycle to full, just like on the test drive, but my TCC slip rpm was still high. That seemed strange, no load/full duty-cycle was showing as much slip as driving with a load on it. You would think if there were an actual slip, the degree of slip would be affected by the load, or lack thereof.

What about that PWM solenoid and the signal to it? Again I went to the PCM, this time commanding the duty-cycle while monitoring it with the DMM, there was no signal present (FIG 4)!

FIG 4

Figure 4

The PCM was showing scan data that made it look like everything was operating as it should be, but there was no actual signal coming from the PCM even though it showed otherwise on the data stream. It could recognize that the slip was not coming down with the duty-cycle going up, and would set the code. At this point it sure looked like we may have a failing PCM. I wanted a second opinion, so I relayed all the information to our lead tech, going over everything that had happened up to this point. He agreed that it sure sounded like the PCM had a problem so I decided to pull the trigger.

A new PCM was ordered, installed and programmed. Several test drives at highway speeds were performed, and the truck showed no TCC slip, and no codes returned. This is the first time I had run into this sort of thing causing this code and symptom, and I can see where it would be very easy to assume that the problem was inside the transmission. Given that everything on the scan tool looked good, countless other vehicles are fixed with a transmission when they act like this. I can only assume that the transmission had already been replaced for this reason once before. It’s always a good idea to verify that what the scan tool is displaying to you is actually what’s taking place. False information results in incorrect diagnosis.

Transmission Issue Creates Symptoms In Other Vehicle Systems

By Sean Mahoney, Diagnostician

mahoney-seanSean has been a member of the Certified Transmission team for five years. He is ASE-Certified and enjoys the challenges that come with diagnosing vehicle problems.

A while back we had a customer come into our shop stating, “The vehicle sometimes has a VSC (Vehicle Stability Control) error and won’t go past fourth gear, but today it seems fine.” The vehicle was a 2007 Lexus LS460 with 132,561 miles, and equipped with an AA80E 8 speed transmission and a 4.6L engine. As with routine diagnosis, I started with a road test, a scan of all modules, and an undercar inspection.

The scan procedure came back with four DTCs: P0771 (shift solenoid ‘E’ performance), P0796 (pressure control solenoid ‘C’ performance), and P2714 (pressure control solenoid ‘D’ performance). There was also an unrelated HVAC code stored. Because there were no VSC or ABS diagnostic trouble codes present, when the check engine light was illuminated the system was possibly turning the VSC system, but at this point it is too early to rule anything out.

On the road test I backed out of the parking spot and started on my normal route. At the first stoplight the transmission clunked into gear while coming to a stop, and when I accelerated I could tell the transmission was in a higher gear. Oddly enough, the vehicle would try to shift once in a while after taking off from a stop, but most of the time the transmission stayed in third gear.

fig1

Figure 1

As I pulled the vehicle into the bay door to do an undercar inspection and to finish my initial evaluation, I put the car in reverse and had a 5 second delay followed by a very, very hard reverse engagement. I tried to duplicate the delay a few more times with varied results, sometimes it went into gear with no issues and sometimes it had a hard delayed reverse engagement. Underneath the vehicle I checked the fluid (which was dark) and I noticed that the wiring coming out of the transmission connector looked oily. Even though the VSC light didn’t illuminate on the initial test drive, I could tell there was still a problem that needed to be addressed. Due to the oil-soaked harness and the solenoid codes it was time to recommend further testing. The customer agreed and left the vehicle with us to proceed.

I wanted to get as much technical information about this transmission (even if it was unrelated to my problem) before I went any further. I took a look at the diagnostic trouble code information and flow charts, and surprisingly the information for P0771 and P2714 directed me to start with P0796 (pressure control ‘C’ performance code) if all three DTCs were present. I started with a simple battery and alternator test, which the vehicle passed. Next, I raised the vehicle back up and proceeded to disconnect and inspect the transmission connector more closely due to the possible fluid weeping through. As I thought, the ATF was pushing through the connector.

fig2

Figure 2

fig2a

Figure 2A

Curiosity got the best of me and I unplugged the transmission harness, let the vehicle down and shifted between park and drive to reverse multiple times. Just as I assumed, I had a reverse engagement every time, albeit very firm and quick, as expected. I carefully disassembled the connector cleaning it with electrical contact cleaner (Deoxit D5), and dried out the connector socket at the transmission. I started next, with checking for B+ at the ECM connectors for the solenoids, next I removed the E6 and E7 connectors from the TCM and started with a simple resistance test through the solenoid circuits.

fig3

Figure 3

The specification for the SLT (P2714) and SL3 (P0796) solenoids (which are linear solenoids) is 5.0-5.6 Ω, and 11-15 Ω for the SR (P0771) solenoid which is one of the two on/off solenoids in the transmission. I found 5.6 Ω at the SLT solenoid and 5.5 Ω at the SL3 solenoid. Both were in spec, but the SR solenoid showed 47.3 Ω when checked. Next, I checked resistance from the transmission connector to the TCM connector to make sure my SR solenoid wiring wasn’t shorted to ground anywhere. I found .3 Ω from the transmission connector to the TCM connectors on all three solenoid circuits. I knew that the probable cause of my problem was the SR solenoid, but since I was already at the TCM and had my scope handy I wanted to see if I could watch the three solenoids before while getting the vehicle to act up.

fig4

Figure 4

When reverse was engaged the SR solenoid dropped from 12v to 0v which showed it was being pulled to ground as it should be. After removing the pan, the SR solenoid checked directly at the solenoid was 47 Ω. I conceived my recommendation: replace the SR solenoid and the internal wiring harness to address the customer concern and the connector leak.

Even though the case connector has plenty of clearance between the valve body and case, the valve body still needed to be removed to unplug sensor wiring above the valve body.

fig5

Figure 5

I removed the filter and unplugged the solenoids. Next, I removed the e-clip that secures the manual valve. There are 17 bolts that needed to be removed, and 3 different lengths used holding the valve body to the case.

fig4

Figure 4

The spring and check ball body above valve body need to be accounted for when going back in. After installing the harness and putting the valve body back in, I installed the new SR solenoid which checked at 13 Ω like it should have. One thing to note is that the transmission fill procedure on this vehicle is very specific and too long to include in this article, so if you work on one of these units be sure to refer to service information when setting the fluid level.

After getting the transmission filled up, checked and rechecked again, I was ready to see how this vehicle is supposed to normally drive.

fig6

Figure 6

The vehicle shifted great, and after a few long road tests I was confident that the original issue was addressed and repaired, so the vehicle was then delivered to the customer.

One month later the vehicle returned to me with the customer complaint of, “The check VSC light is on, but it is shifting okay at this time.” This time the VSC light was illuminated along with the check engine light. A quick code scan revealed a P0171 (system too lean bank 1), and C1201 (engine control system fault) which sets the check engine light and the VSC light. It’s usually never a great thing when a vehicle comes back, but in this case I could verify the transmission operation over a longer period of time and refer the customer to a shop that could address his engine-related codes.

I wanted to bring attention to this one because one of the issues that we have seen lately is other shops not spending time to look at all things related to a warning light. This nearly identical circumstance had happened previously where the customer took his car to a transmission shop with the VSC light on and was referred to a general repair shop because, “We don’t work on that stuff” prior to even hooking up a scan tool. The customer then goes to a general repair facility where he is told that’s a transmission problem and, “We don’t work on transmissions”, and then finally to one of our locations where the customer issue is finally repaired. You can see how frustrating this could be for anyone getting this poor level of customer service. The takeaway is to know and understand the various systems that are involved in your diagnosis, and how they relate to each other.

Heat-Damaged Harness Causing P1860 Code – 4L80E

By Randy Peterson, Diagnostician

peterson-randyRandy has worked for Certified Transmission for over twenty four years and is an ASE Certified Master Technician, including L-1. He has been in the automotive industry for over 30 years.

1999 Chevrolet C30 7.4L 4L80E

The subject vehicle that was fitted with one of our remanufactured transmissions 6 months prior showed up at one of our repair locations recently, with the customer concern of an intermittent bumpy 1-2 shift, and a low power lugging sensation along with a CEL on. While performing our initial evaluation, we found a P1860 code stored in history, but not current. During the road test the truck was working well with no clear signs of what set the DTC, but after several minutes of driving it then started to act up. The TCC was applying right on top of the 1-2 shift, but according to the scan tool data, was not being commanded on by the ECU.

To diagnose the issue, a wiring diagram and a code description were printed and reviewed; this is a typical circuit for a GM transmission. The fuse feeds power to the transmission shift and TCC solenoids through pin ‘E’ at the case connector, and the power then runs through the solenoids and back to the VCM. The VCM is responsible for grounding the circuit to energize the solenoids. The TCC solenoid in this application is a PWM type and the computer duty cycles it on to provide a smooth engagement. A comprehensive battery and charging system test was performed to make sure that there was adequate voltage for proper circuit operations.

With this knowledge I decided to first check to see if there was B+ at pin ‘7’ (brown wire at the C2 connector of the VCM) with KOEO. [FIG 1] If there wasn’t any voltage drop at that location I knew the circuit was complete with no opens or shorts to ground, and if there was a voltage drop I would start backwards from the VCM to look for an open/short in the circuit. There was B+ at pin ‘7’, so I hooked up my scope to test the circuit with the scanner using the bilateral controls and then drive the vehicle to see if the problem would occur.

FIG 1

Figure 1

I back-probed pin ‘7’ at the VCM to monitor the voltage with my scope lead, and then I put an amp clamp around the brown wire to monitor amperage [FIG 2]. Using the Tech2Win software to cycle the TCC solenoid, I could see the voltage drop to 0 and the current went to approximately 0.8 amps. The specification for the solenoid is 10-15 ohms. Using Ohm’s Law I could quickly see that the amp reading was close without pulling out my calculator, at least close enough that it would not trigger a code. Now it was time to run the cables into the cab and go for a test drive.

FIG 2

Figure 2

After driving a couple of miles the engine temperature was up and the TCC came on. The pattern was picture perfect. The VCM cycled the PWM solenoid and then completely grounded it to apply TCC fully. The amperage was what I was expecting to see [FIG 3].

FIG 3

Figure 3

It took quite a few more miles before the incident recurred. I took off from a stop, shifted to second and TCC was fully applied. I looked at the scope and saw that the voltage was very erratic but near zero, the amperage was at zero and the DTC also set. How could the voltage be at zero with the TCC is on, and there is NO Amperage going through the circuit? [FIG 4] Smarter men than I would know the answer to this right away. I just could not wrap my head around it at the time. Solenoid on, TCC applied, no current flow. I had to sleep on this one.

FIG 4

Figure 4

The next day Carman (shop Diagnostician) and I were discussing how there could be a completed circuit, the TCC solenoid on, TCC working and no amperage in the circuit. We were ready but not willing to replace the VCM. We then noticed a harness at the rear of the engine lying on the EGR tube. We lifted it up and used a mirror to see if it had burnt through, and it had [Fig 5].

FIG 5

Figure 5

We determined this was the main harness to the transmission and our TCC control wire was in there. We strapped the harness up and away from the EGR tube and went for a drive [FIG 6].

FIG 6

Figure 6

The transmission and the TCC worked flawlessly. Carman then dissected the harness and found our brown wire was burnt and shorting to the EGR tube. [FIG 7]

FIG 7

Figure 7

After a few minutes of thought, the mystery in my mind was solved. There were supposed to be a couple of harness retaining clips that held the harness up off of the EGR tube that were missing/broken that allowed the harness to come in contact with the EGR tube. There was also still enough wire insulation left that when it cooled off the short to ground was not present until the EGR tube got hot enough to melt through the insulation and bring the circuit to ground. So why did the circuit ground, solenoid function, TCC on and no current detected in the circuit? It was my current clamp placement! The circuit was completed at the EGR tube from the fuse instead of the VCM supplying ground. My amp clamp was outside of that circuit, as I had placed the amp clamp very close to the VCM connector C2. The VCM in turn would not ground the circuit because the code had set once the brown wire touched the EGR tube and no longer sensed voltage at the VCM. Had I used a fuse buddy loop and had the amp clamp at the fuse box, I would have seen the amperage when the wire shorted. At that point I could have certainly condemned the VCM for randomly grounding the circuit and I would have been very wrong. Sometimes it’s good to be lucky.

Note: Someone, a.k.a. me, did not zero his amp clamp on some of the scope captures. That is why it looks like it is below 0 amps.