What this usually means
Known balance shaft gear failure on M271 EVO engines (2009-2010 production). If your engine is in the affected serial range, this is 90% the cause — and Mercedes-Benz HAS issued goodwill repairs in some cases. ALWAYS check serial number against the M271 recall list BEFORE accepting any repair quote.
What to ask the workshop before approving repair
- • Show the diagnostic fault codes.
- • Show photo/video proof of the failed part.
- • Give an itemised quote for parts and labour.
- • Explain why cheaper common fixes were ruled out.
This is not a final diagnosis. It is a money-saving checklist before you go workshop.