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 S500 4MATIC Wire Connector on Transmission May Leak Fluid and Damage Control Module
Mercedes-Benz S500 4MATIC Problem
Visitor, 2004 Mercedes-Benz S500 4MATIC, 60,000 mi
leak at harness connector to transmission, should be repairred and paid by mercedes. only 60k on the car. 2004 s500 4matic. At dealer and they are replacing the o ring seal.