Welcome to my nightmare. Had same problem last week- required Wiring Harness, and Throttle Actuator. Dealer paid parts cost on Wiring Harness, but I'm still out $1500. This after having a water pump and Battery replaced last week. Lousy track record for a garaged, Dealer serviced '94 E320 with 86k on it. This is my 3rd MB, but it may well be my last.