annistorm1
Mercedes S Klasse EGR Valve Problem
Summary of the thread
A 2009 Mercedes S Klasse with a gasoline engine is experiencing issues such as a check engine light, reduced power, smoke, rough running, high fuel consumption, jerking, and a hissing sound during acceleration. These symptoms suggest a potential EGR valve failure, possibly due to carbon buildup or a jammed valve. The recommended solution is to inspect and potentially replace the EGR valve for reliable performance and emissions compliance. After replacing the EGR valve, the vehicle runs smoothly, resolving the issues.
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4 comment(s)
annistorm1 (community.author)
I haven't pulled the codes yet, but I will tomorrow. Where should I look for carbon buildup on the EGR valve? If it is buildup, can I clean it, or should I just replace the EGR valve?
lisastorm16
Cleaning might be temporary given the mileage. The valve mechanism could be worn. Remove the EGR valve and inspect the valve seat and pintle for carbon deposits. I'd lean toward replacing it for a reliable emissions test and proper running. Replacement is likely the better long-term solution for optimal recirculation.
annistorm1 (community.author)
Thanks! The codes confirmed it was the EGR valve. I replaced it. The workshop charged me 355€ including parts and labor. It runs great now, no more smoke or jerking, and the check engine light is off! Hopefully, it will pass the emissions test. Thanks for the help!
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MERCEDES
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SKLASSE
lisastorm16
Sounds like EGR valve failure. The symptoms point to it being jammed. The hissing could be exhaust leaking. Have you checked the EGR valve for carbon buildup? What codes are you getting?