Peugeot 206 exhaust leak and sensor issue

I had a similar issue with my 206. Symptoms sound familiar. Have you checked for any obvious exhaust leaks before the sensor? A leak could definitely throw off the sensor readings. What kind of readings are you getting from the sensor?

Where exactly did you find the leak on your Peugeot, and were the sensor readings completely off the charts? Any chance you remember what the sensor was reporting?

I didn't check the sensor readings before taking action, to be honest, but the leak was near the manifold gasket. Given the symptoms you described, I suggest taking your car to a workshop for a proper diagnosis.

Thanks a lot for the info! Took it to a shop, and you were spot on. Turns out there WAS a small leak in the exhaust manifold, which screwed with the exhaust temperature sensor. Sensor replacement and manifold repair set me back 265€, but at least it's fixed!