Xsara NOx Sensor Failure Exhaust Leak

Xsara owner here. NOx sensor issues are common. Is it definitely the sensor itself? Have you checked the catalytic converter? A faulty converter can trigger similar errors.

Converter seems okay, though I haven't fully ruled it out. Code reader points directly at the NOx sensor. Did your issue present with a noticeable exhaust leak as well?

The leak might be a separate issue, but I did have a similar code. Ended up being the sensor in my case too. Probably best to get it properly diagnosed at a workshop to be sure.

Thanks. I'll take it in. Turns out it was the NOx sensor cable. Replaced for 95€. Pollution control is now working.