The camshaft adjuster solenoid (which is related to the variable valve timing system) may fail or timing chain/balance shaft components may wear, resulting in illumination of the Check Engine Light and various drivability issues. Mercedes-Benz has released a service bulletin outlining specific repair instructions depending on fault codes stored.Google+
Car Problem Reports
Mercedes-Benz C350 Camshaft Adjuster Solenoid Failure
Mercedes-Benz C350 Problem
Average Mileage: 68,475 mi (42,000 mi - 81,900 mi)
Same problem. Quote to repair ZAR 24,000. Where can I get hold of the buletin Mercedes issued?
Visitor, 2008 Mercedes-Benz C350, 70,000 mi
rough shifting occassionally,especially coasting down hills. Check engine light came on, code was for a bad solenoid. Told not that big of a problem
Visitor, 2007 Mercedes-Benz C350, 42,000 mi
One week before my warranty ended, I brought my car to Mercedes Benz of El Dorado Holls. They fully serviced the vehichle, for a cost in excess of $1,200.00. I told them to make sure everything was checked and repaired during this last major service and if anything was wrong, to please make sure my warranty covered it. The next day the Check Engine light came on and I brought the car back to the same dealer for them to check. They took the car in the shop and brought it back about a hlaf an hour later and said the oil needed to be topped off and all was OK now. Over the next 4 months we drove the car less than 300 miles. The check engine light came on again, my warranty has now ended and the same dealership wants $5,300.00 to fix it. Of course, since they told me to just drop by and they would take a look at it, there is NO record of them looking at it. This is WRONG...and they are trying to contact Mercedes to see if they will cover the costs...we shall see how good MB of El Dorado Hills really is.