C Klasse exhaust treatment malfunction

I had a similar issue with my C Klasse The malfunction was related to the oxygen sensor The engine management system detected an incorrect reading and triggered the check engine light Have you checked the sensor's wiring for any obvious damage

Thanks for the quick response I haven't specifically checked the wiring yet but I will definitely take a look Was your exhaust also smelling strongly and did you notice any change in fuel consumption What was the error code you got I'm trying to get a better handle on this before I potentially start replacing parts

Yes the exhaust smell was definitely stronger than usual and fuel consumption increased noticeably I didn't read the code myself Given the symptoms and the fact you suspect a defective oxygen sensor I'd recommend getting it properly diagnosed by a workshop They can pinpoint the exact cause whether it's the lambda sensor or something else related to the exhaust system

You were spot on I took it to the workshop and it was indeed the lambda sensor They replaced it and the exhaust smell is gone the engine is running smoothly again and the check engine light is finally off Total cost was around 375€ which is thankfully less than I feared Thanks again for your help