C3 Oxygen Sensor Heater Failure

I also have a C3, and had something similar a while back. Same symptoms, check engine light and higher fuel consumption. I didn't check the error codes myself, but the garage mentioned it was something to do with the exhaust system sensor. Did you check the sensor itself? Maybe it's just a faulty sensor?

Thanks for the quick reply! When you say you had something similar, was the error specifically related to the oxygen sensor heater circuit, or just a general oxygen sensor fault? Also, did you try testing the sensor or the wiring at all, or did you just go straight to replacing the sensor? I'm trying to avoid unnecessary expenses.

To be honest, I can't remember the specifics of the error code. I just remember the garage saying it was the oxygen sensor. I didn't do any testing myself; I'm not really that mechanically inclined. I'd say it's best to take it to a workshop. They should be able to diagnose it properly. Could be the cable after all. If it's the sensor, it should be a quick and cheap fix.

Thanks for sharing your experience. I appreciate the advice. I ended up taking it to a local mechanic, and you were right - the cable or plug connection of the component was defective. They replaced it and the error is gone. Total cost was 95€ Saved me a lot of time and hassle!