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. A new harness and control module may be necessary to correct this problem.Google+
Car Problem Reports
Mercedes-Benz C240 4MATIC Wire Connector on Transmission May Leak Fluid and Damage Control Module
Mercedes-Benz C240 4MATIC Problem
Average Mileage: 78,666 mi (12,000 mi - 106,000 mi)
Visitor, 2004 Mercedes-Benz C240 4MATIC, 12,000 mi
Very early on after purchase transmission shifted poorly. Under warranty dealer replaced transmission.
Visitor, 2004 Mercedes-Benz C240 4MATIC, 101,000 mi
transmission went into limp mode. Dealer said fluid had got into control module.
also said that they were seeing a lot of this happen
Visitor, 2003 Mercedes-Benz C240 4MATIC, 102,000 mi
fluid leaked up the cable going to the tcu. Faulty boot let fluid reach the TCU, shorting it out somehow. now the Tranny won't engage and has caused physical damage requiring transmission replacement. still parked. still paying monthly storage and loan payments. Thanks MB!!
Visitor, 2004 Mercedes-Benz C240 4MATIC, 50,000 mi
delay in up-shift; hard shifting; my mechanic found the leak and cleaned the harness and TCU pins avoiding a replacement of the entire harness.
Visitor, 2005 Mercedes-Benz C240 4MATIC, 67,000 mi
A/T plug assembly replaced.This is not a mercedes covered item based on the mileage...correct?
Visitor, 2005 Mercedes-Benz C240 4MATIC, 75,000 mi
the car drives in tow mode. unable to get out of tow mode. transmisssion light stays on