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 SL550 Camshaft Adjuster Solenoid Failure
Mercedes-Benz SL550 Problem
Average Mileage: 51,700 mi (2,100 mi - 80,000 mi)
Had it 1 week check engine light came on, code P0015
Visitor, 2007 Mercedes-Benz SL550, 66,680 mi
I Just purchased my vehicle two days ago and the engine light came on with a P0015 code...wow a little frustating for a problem to appear so quickly...
May 13,2013 purchases 2007 Mercedes Benz SL550 hard top convertible. Drove it once that weekend. Parked it in garage. Two weeks later, took it out for a drive and check engine light came on. Took it back to Carmax, they say its a solenoid and repair is covered under warranty I purchased. My deductible is $200. Thoughts anyone ? I could not tell any difference driving because I only drove car some 50 miles total since purchasing it. Prior it was a "fleet car" with a clean car fax history.