Allpar Forums banner
1 - 8 of 8 Posts

·
Registered
Joined
·
3 Posts
Discussion Starter · #1 ·
Hello all,
New to the forum here and trying to help out my dad. He recently purchased an '06 PT Cruiser knowing it had a transmission shifting problem. He was told it was the PCM so he ordered a programmed, remanufactured PCM and installed it. The problem still exists. CEL on and doesn't shift passed second gear. The codes are as stated in the title, P0700 & P0882. I've done some searching on this forum & others as well as YouTube. Based on what I'm seeing, it isn't the first time this car has had this problem. The TIPM has already been replaced with a remanufactured Dorman unit. The grounds next to the TIPM have all been cleaned and secured. I followed the troubleshooting steps outlined in this video:
This is where I'm getting stuck, when I turn the ignition to ON and meter the wires mentioned in the video, I get a little over 12V on the light green wire and the red wire for about a second and then the voltage drops out. So the TIPM and relay inside of it appear to be working. I'm trying to figure out what is causing the voltage to drop out coming from the PCM on the light green wire shortly after turning on the ignition.
I've found wiring schematics but nothing that seems to me to indicate where the light green wire source is other than the PCM.
TIA for the help.
 

·
Registered
Joined
·
5,271 Posts
. . . New to the forum here and trying to help out my dad. He recently purchased an '06 PT Cruiser knowing it had a transmission shifting problem. He was told it was the PCM so he ordered a programmed, remanufactured PCM and installed it. The problem still exists. CEL on and doesn't shift passed second gear. The codes are as stated in the title, P0700 & P0882. I've done some searching on this forum & others as well as YouTube. Based on what I'm seeing, it isn't the first time this car has had this problem. The TIPM has already been replaced with a remanufactured Dorman unit. The grounds next to the TIPM have all been cleaned and secured. . . . .
P0700 is generic and just indicates you need to search farther and find one or more transmission diagnostic codes.

. . . . This is where I'm getting stuck, when I turn the ignition to ON and meter the wires mentioned in the video, I get a little over 12V on the light green wire and the red wire for about a second and then the voltage drops out. So the TIPM and relay inside of it appear to be working. I'm trying to figure out what is causing the voltage to drop out coming from the PCM on the light green wire shortly after turning on the ignition. . . . .
According to factory service manual code P0882 is set when there is less than 3.0 volts present at the transmission control output circuits located in the PCM when the TCM (transmission control module part of PCM) requests the power up of those circuits.

At power up with ignitioni key switch turned to the RUN position, the TCM is checking the circuitry. It senses less than 3.0 volts as noted above. It then disables the power up signal to the TIPM (on the green wire). The TIPM receives the disable signal and thus cuts power on the red wire to the PCM.

Attached is a better diagram of the transmission control circuitry between the PCM and TIPM. In the video you referenced the technician is using a non-factory wiring diagram source. Note that connector C102 is not shown in the schematic but splice 136 is shown. The diagnostic codes indicates low voltage so that would lead one to believe there is excessive resistance in the circuitry. Check connector C102 for good, tight fit and cleanliness of the pins to the receptacles. Check splice 136. There could be corrosion / bad crimp where multiple wires are joined.

Unfortunately I am thinking the technician in the video called a failed TIPM and fired the "parts cannon" and that was NOT the cause. Bad connections in the wiring is my hunch as to the source of the problem.

Rectangle Font Line Slope Parallel
Organism Slope Font Parallel Auto part
 

·
Super Moderator
1966 Crown Coupe, 2016 200 S AWD, 1962 Lark Daytona V8.
Joined
·
23,674 Posts
Welcome to Allpar. The TIPM is 'smart' power management. It has a micro-processor and can store fault codes and run tests with a capable scan tool as well.
It is not OBD2, so a more specialized scan tool may be required for reading TIPM codes.

If you are reading just the PCM/TCM codes, you may just be getting half of the story.
Armed with the full story and following the diagnostic procedures, there should be no need to guess what the issue is.

Possible TIPM fault codes related to the TCM:
  • P128B-TCM POWER CONTROL CIRCUIT 2 LOW
  • P128C-TCM POWER CONTROL CIRCUIT 2 HIGH-41TE NGC
  • P128D-TCM POWER CONTROL CIRCUIT 2 OPEN-41TE NGC
  • P128E-TCM POWER CONTROL CIRCUIT 2 OVERCURRENT-41TE NGC
 

·
Super Moderator
Joined
·
33,378 Posts
Just as an indicator of how theory matches real life:
I'm an engineer with 40 years experience with electronic components, reliability and plating metallurgy. Many of these so-called 'computer failures' are actually interconnect failures. Micromotion (less than a mm) from vibration causes fretting corrosion at the mating surfaces of connector contacts, which can expose base metal which then oxidizes, or if the connector plating is tin, can cause tin oxides to ball up and create intermittent contact or high resistance. Plugging and unplugging the connectors often removes the oxides, so for anyone changing out a computer, and finding that the 'new one works', they believe that they are validated in their belief that the old one died. When in fact, it was a connector issue.
Last year, I had several instances in my Chrysler 200 where I got skipping and then a crank-no-start, along with CEL and codes indicating loss of 5V power to the PCM, along with a crankcase position sensor fault. Many parts-swappers would have installed a new PCM ($600) and a crank sensor ($50 or more), and the problem would have gone away for awhile. In fact, I found that there are two 96-position connectors to the ECM, and most of the pins are silver-plated, which can oxidize; and there are a handful of pins that are gold-plated, for low-level sensors. I removed the PCM, cleaned its male contacts with an electronics contact cleaner, and sprayed it into the female contacts in the plugs (too small to use a Q-tip), and did remove some tarnish from a few pins.
It worked flawlessly for 1,000 miles, then I had a crank-no-start when I stopped at a convenience store near the end of a trip. Third try, it started and has been fine since for a few hundred miles.
It's not the PCM. It's tarnish on the contacts. Cleaned and fixed for nearly free. The fact that it recurred once indicates that I may need to clean those specific pins more.

So, look to the connector contacts on both sides to see if that's your issue.
 
  • Like
Reactions: AllanC

·
Registered
Chrysler PT Cruiser
Joined
·
87 Posts
Hello all,
New to the forum here and trying to help out my dad. He recently purchased an '06 PT Cruiser knowing it had a transmission shifting problem. He was told it was the PCM so he ordered a programmed, remanufactured PCM and installed it. The problem still exists. CEL on and doesn't shift passed second gear. The codes are as stated in the title, P0700 & P0882. I've done some searching on this forum & others as well as YouTube. Based on what I'm seeing, it isn't the first time this car has had this problem. The TIPM has already been replaced with a remanufactured Dorman unit. The grounds next to the TIPM have all been cleaned and secured. I followed the troubleshooting steps outlined in this video:
This is where I'm getting stuck, when I turn the ignition to ON and meter the wires mentioned in the video, I get a little over 12V on the light green wire and the red wire for about a second and then the voltage drops out. So the TIPM and relay inside of it appear to be working. I'm trying to figure out what is causing the voltage to drop out coming from the PCM on the light green wire shortly after turning on the ignition.
I've found wiring schematics but nothing that seems to me to indicate where the light green wire source is other than the PCM.
TIA for the help.
Easy peasy lemon squeezy. Wife's '06 PT Touring had this issue for 6 years. After I bought the car off her, I wanted to fix the issue. I did a temp fix in an evening, and permanent fix in a matter of days.

The fault developed on my PT at 101,000 and persisted to around 140,000/5years. I have done some 18,000 miles and had 18 months since I performed my fix, and have experienced zero codes or engine lights. That's at least testament, to the fix on my car.

Workaround fix:

You need to wire in a relay that connects to the green ignition wire on the PCM harness, and connects to the 12v Transmission wire also and ground/fuse it. This will ensure that whenever the car is on, the transmission will get the 12v it needs to perform shifting functions. I'll see what documents I have lying around, I put together a full instruction set for how to do this - but suffered some data loss not long after.

Permanent fix:
Disclaimer: SINCE THIS IS PULLING AN UNTESTED, USED PART THERE IS NO GUARANTEE. THIS IS AT YOUR COST, I TAKE NO RESPONSIBILITY. SINCE MY JUNKYARD PCM COST ME $20, I WAS HAPPY TO RISK A LOSS.

Go to the junkyard. Find an '07 or '08. You need to find one that similarly matches your car, here is the criteria:

If you have fogs, find one with fogs. If you dont have fogs, find one that does not have fogs
If you are N/A, find an N/A - If you are turbo, find turbo
If you are automatic, pull from an automatic - if you are manual, this doesn't apply


Either way, pull from a model that is similar. I have an '06 PT Touring 4 door. I pulled from a red '08 PT Limited Edition. You need to pull the PCM. Before slapping it in your car, you need the VIN from YOUR car to be flashed to it. I used a shop in Florida I found online called Vegter Auto (Info below). I had them flash my VIN. Since I'm in KC, I had to mail it. The procedure was: I pay for mailing there, I pay $50 for the flashing process, then cover return mail cost back to me. This took 4 days total. Once you have your programmed PCM, disconnect the battery and drain the power. Swap your bad PCM to the used one. Reconnect battery, and take on a short test drive so it can establish it's values and you can verify shifting works.

So what's the cause of this issue?

Poor heat deflection/removal in the '06 PCM, combined with less solder than later models. This means over time and repeated hot/cool cycles the solder joints weaken and cause random disconnections, or voltage drops. This is why you may notice the issue occurs more in cold weather than hot weather. As the solder heats, it's more liquid and thus flows and makes connection. In the cold, it's still frozen and the connection breaks. I've disassembled my old faulty PCM to confirm this.

Ordering a 'reman' unit through companies like FS1/Flagship 1 is not always a good solution. They charge a fortune. And the units are not even rebuilt properly in my experience. I got through 3 of these prior to losing my temper with the entire thing, taking a $200 loss and just going and getting my own PCM.

This issue is constantly mis-diagnosed as a TIPM issue, when 99% of the time the TIPM is totally fine. It's quite rare for the TIPM to actually fail, it's just a fancy name for a plastic casing with relays and fuses in it, it's such a basic component that it does not even need to be programmed to a car.

Resources

My fault codes.

Font Asphalt Logo Darkness Screenshot


These wire colours correspond to the 4pin relay wire colours. The C# references the connector. C1 is the first PCM connector, C2 is the second etc. Since I reference C4 in the document, this is the green PCM connector. The numbers (87 - 30 - 86 - 85) refer to the number on the relay, if you check the relay it is labelled with these numbers.

Font Writing Paper Document History


You'll need some cuts of wire, a 4pin relay from Autozone and an inline fuse holder with 20a fuse to run to the battery for the direct 12v feed. It's not a hard job to do, but will require you splice into the green ignition wire in the pigtail, and the red one also. I want to express, this is NOT a permanent fix. If you have bad solder joints in your PCM module in the TCM portion, other faults with come in time. After a period of time just using the bypass on the bad PCM, I experience a crap ton of error codes due to other failures in the PCM. Everything from Cyl3 misfire, fuel bank pressure errors. Ultimately, you want to replace the PCM as I showed. This is just a temporary workaround. Though it should be noted, you can keep this fix in place after you replace the PCM. I did this on mine as insurance. My TCM issue had gotten so bad it started throwing the transmission OUT of drive, one day this happened on a single lane highway at highway speeds and I had to bail into a ditch.
 
1 - 8 of 8 Posts
Top