Transmission May Leak Fluid and Damage Control Module on Mercedes-Benz CLK500

The electrical connector at the automatic transmission may leak fluid into the wiring harness. If not repaired, the oil will migrate through the wiring harness and damage the transmission control module. At that point, a new harness and control module may be necessary to correct this problem.

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Average mileage: 70,515 (32,000–125,125)
4 model years affected: 2003, 2004, 2005, 2006 more
14 people reported this problem
8 people shared problem details
The transmission control module got damaged (shorted)by transmission fluid leak. Has to be replaced.
3 people like thisFlag inappropiate
Tranny leaking fluid on harness and into control module. Just found out that there was no tranny fluid as it wasnt shifting. Shop says that they only solution is to have it checked and cleaned on a regular basis. Is there a permanent solution?
1 person likes thisFlag inappropiate
Transmission began failing to shift, so we would stop the the car and turn it off and then the car would shift again. I changed the fluid in the transmission but did not change the transmission adapter plug. I later found out that fluid had wicked up the harness into the tcu. The car then went into limp mode. By the way the fluid in the transmission was filthy brown an indication that coolant from the radiator was being mixed in with the transmission fluid. I scanned the the car and got codes p0730 and code p0715. I then changed the valve body and the conductor plate to include all new shift solenoids, but the problems persist. I took the car to an indy and he sad the transmission needed to be rebuilt. I don't buy it and I decided that I will get a second opinion. The second guy said he has seen this exact thing before an an ml and all he did was change the wiring harness and the tcu and reset the codes and the car was fixed! I do hope that this will be my problem as well. I'll keep my fingers crossed!
Advised by dealer to fix. Declined.
The trasmission started going into nuteral when downshifting and would sometimes upshift slowly. The Check Engine light came one, the went off a few times. Took the car into the local MB dealer who pulled some codes indicating tranny problems. When they checked they found the fluid leak and fluid wicking into the module shorting it out. Est. repair is $1,500. This leak was spotted by another shop about 50K miles ago and supposedly fixed, guess they didn't do a very good job of it. It's hard to catch a tranny fluid leak since this car doesn't have any way for the owner to accurately check the transmission fluid level. Thanks MB.
Delayed shifting from stop to lower gears. No shifting into higher gears, irratic. Came on suddenly - not gradually as one would expect. Took to first mechanic who observed tranny fluid on wire harness between tranny and tranny control module (TCM). No error codes on tranny when checked with computer. Took to MBZ specialist (non dealer). Same observation but could not get codes from MBZ in Germany to reprogram new control module. He suggested take car to dealer. So, I am hopeful it is only the harness and/or TCM. Has anyone had this experience? what can I expect to pay if this is what the dealer finds?
complaint of leak at wire connector may cause wiring harness to be replaced, never performed and now have almost 250000 miles
Repaired seals prior to damage of control module $330
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