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I'm hoping someone can help me with an issue on my recently acquired car. During a long motorway drive home the car dropped out of gear and I had to coast to the hard shoulder, after turning the car off and back on again I was able to drive a short distance before it would drop out of gear again. I had the car towed to a auto box specialist and the following codes were present:
Gearbox:
P2600 - the voltage of supply circuit 87 has undervoltage
P2500 - the transmission has an impermissible ratio
P2502 - the gear is implausible or the transmission is slipping
P220A - the speed comparison of Y3/6N2 to Y3/6N3 is implausible
Engine:
P0600-008 - CAN fault, the stored transmitter is faulty
P1664-002 - electric heater stored fault
Selector:
P1817 - Back light KI. stored 15 voltage supply error
Their report stated that there was very slight Glycol contamination determined from a sample of fluid and the recommended changing the radiator and torque converter initially followed by a rebuilt transmission of the problem persisted.
Following this report I drove the car home 20 miles without fault. I then did some research and found that the car has a BEHR radiator which as far as I'm aware never suffered from failure of the transmission cooler, this was only Valeo. I then managed to get in contact with the previous owner of the car (they sold it via an auction to a dodgy dealer who then sold it to me) and they informed me the car had an exchange gearbox only 2 years ago from a 60k mile car (no proof of this mileage however) due to the original box slipping, unfortunately they couldn't tell me if the torque converter was swapped out at the same time.
I'm really not sure what to do, I'm not sure if I can trust the transmission specialist as I don't see any reason why the box should be contaminated (unless of course the replacement 60k box came from an affected car...) and I don't see why a 60k mile box would be causing these faults.
When I spoke to the dealer that sold it to me he said that if the battery has died (which it did) it can cause these issues with the box - the fault code P2600 could be evidence of this? And given that the car drives ok now may prove this point?
Do any of you guys have a more plausible explanation or can offer me advice on what to do next?
The car is a 2003 model year and has a 722.699 5 speed gearbox.
A. Your tranny sends communication thru a adapter plug at the transmission- up thru a electrical cable - into the Transmision Control Module (TCM) in the engine compartment. That adapter plug tends to leak internally - fluid "wicks up" thru the cable to contaminate the TCM board. One 1st step is to replace that transmission adapter/plug (with genuine MB or Mopar part only) and pull and flood clean the TCM board with MAF cleaner. See the "stickies" in this forum for details. Until you can guarantee clean communication the codes you receive may be true or false.
All the tranny codes could be bad-communication or could be a sign of failing conductor plate in the tranny which can be easily replaced.
B. If you have contamination in tranny fluid - suggest 2nd confirmation - thats a major/major - normally you would see "coffee colored" contamination in the coolant as well - if there has been contamination - then yes - the radiator needs to be replaced - and transmission needs to be drained/refilled - and "most" of the time contamination leads to premature and dramatic tranny failure.
Thank you. I've ordered the plug & contact cleaner and will get it swapped out next week when I'm home. I've also managed to source some Glycol test strips so I will conduct my own test on the fluid but these have a longer delivery date so my plan is as follows:
Change electrical plug without draining fluid (I've read this is possible if you jack the car up on one side only) whilst attempting to get a sample of oil for testing, clean the TCM board with contact cleaner as described in the thread you recommended. I will then start using the car again locally to see if I get any issues, once the test strips arrive I will test the fluid sample, if I find contamination I will change the fluid, possibly the conductor plate and of course the radiator. Has anyone heard of BEHR rads failing?
In an ideal world the test strips will turn up next week so I can do this all in one hit...
Yes - if radiator fails at the tranny cooler - major mix of oil and tranny fluid - "coffee" color on both engine & tranny - look in the cooling system reservoir NOW - and if you have tranny dip stick check TRANNY fluid color/content NOW
OK, I got to work on the car today and here are my findings. Transmission fluid is very dark, almost black. I tested it for Glycol and it seems to be off the charts but I've asked for guidance from the manufacturer to be sure. Checked the coolant and it looks perfect so no issues in the expansion tank? See pics below
Send pictures of test strips to the manufacturer and they confirmed there is no glycol present but the oil is very dirty as I already knew. Drained the oil (unfortunately no drain on torque convertor) and changed the electrical plug on the gearbox, fitted new filter and topped up with around 4l of oil. Removed the TCM module which was full of oil, cleaned it up with electrical contact cleaner and refitted once it had dried out, same treatment for the plugs electrical plugs too.
So far I've driven 80 miles without an issue, checked and double checked the fluid level and it's where it should be. Driven it quite hard for the last 40 miles too.
I will change the gearbox oil again after a few hundred miles to reduce the amount of the old fluid in the system, I think I'll probably do that 3 times or so over the next few months if the gearbox continues to work correctly.
Thanks for all your help with the issues and let's hope it stands the test of time 👍
03-05-2019, 11:28 AM
