One problem related to engine exhaust system has been reported for the 2004 Mercedes Benz C230. The most recently reported issues are listed below.
This is a 2004 mercedes C230. Check engine light went on. I went to dealer within 5 miles of warning light coming on. I was told that there was an oil leak and that it had dripped over several components and the wiring harness. I would cost $3,500 to repair but they absorbed the labor cost and it should cost about $2,000. I have never missed a maintenance on this car. They said the this happens because of where the O2 sensor that leaked is. It seems odd to have minor issue cause such enormous damage.