R Klasse exhaust treatment malfunction

My R Klasse, a 2010 gasoline model, has the check engine light on, is running rough, I smell exhaust, and it sounds like there's an exhaust leak. Mileage is 53407 km. I suspect it could be the lambda sensor.

4 comment(s)

Sounds familiar. I had similar issues with my R Klasse exhaust leak and engine light. Check the EGR valve and exhaust pipe for cracks too. Could be a simple fix.

EGR valve? Is that a common failure point? Any specific symptoms related to that, or just the exhaust smell and rough running?

Yeah, pretty common. If the engine light is on, could be the EGR. The exhaust smell points towards an exhaust leak as well. If you’re not sure, better get it checked at a workshop.

Thanks for the tip. Took it to the shop, lambda sensor was indeed defective. They replaced it, and cost me 375€. Runs like new now.

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