Peugeot 207 exhaust smell rough running

I'm pulling my hair out! I've got a 2011 Peugeot 207, gasoline engine, with nearly 300k kilometers. Recently, the check engine light's been mocking me, and the engine's running rough. I'm getting a strong exhaust smell, and I'm pretty sure there's an exhaust leak somewhere. Could it be the catalytic converter? Or maybe something to do with the particulate filter, even though it's a gasoline engine? I've read a bit about NOx sensors malfunctioning, too. Any ideas before I end up selling it?

4 comment(s)

I also have a 207. I had similar symptoms a while back. Check engine light, rough running, and a weird smell. Could be a lambda sensor?

A lambda sensor, huh? Where exactly is that located, and how would I even check if that's the culprit? And how does a bad lambda sensor cause an exhaust leak?

The lambda sensor is usually near the catalytic converter. I don't know exactly how to check it yourself, to be honest. It didn't cause an exhaust leak on mine. Just the smell and the rough running. It might be better to go to a workshop.

Thanks for the tip! Took it to a shop and you were spot on - defective lambda sensor. They replaced it, and the exhaust smell and rough running are gone. Cost me 375€, but at least it's fixed!

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