After inserting key - there is no response. Tried several times. FOB locks and unlocks the doors. After a couple of days - it started with no problem. A week later, we are having the same problem with no response after inserting the key in ignition switch. This troublesome to know that I cannot rely on the ignition switch working all the time.

- Boonton, NJ, USA

Delay and no start condition when turning the ignition key

- Reno, NV, USA

Control unit failed. Had to be towed to mb dealer.failed unit was replaced with remanufactured unit 1-204-900-59-12-80. Cost $1215.89. Has the problem been corrected with the remanufactured unit or is this an ongoing problem. This time the unit failed in a parking lot. Failure on the highway would be a safety issue.

- Huntington Beach, CA, USA

Security module failed which locked steering and prevented car from starting. Had to toe to dealer and repair was $1000. Many complaints and hundreds of similar failures on this and C class models on internet. This failure stranded my wife in another city and should be considered a safety defect. Vehicle had just been driven to a doctor visit but refused to start after visit. Mercedes roadside assistance technician knew exactly what was wrong when called to the car and stated he had seen dozens of this failure in only the past few months.

- Tega Cay, SC, USA