Citroen C3 knock sensor issue

I had almost the same symptoms on my C3. Check engine light, rough idle… it was driving me nuts! Have you checked the sensor itself for any physical damage or corrosion? It could be the sensor, but a faulty connection is also very probable. I would start by inspecting the wiring and the plug.

Thanks for the quick response. I've visually inspected the sensor, but didn't notice anything obvious like cracks or breaks. Where exactly should I be looking for corrosion or damage in the wiring? Is there a common weak spot in the C3's wiring harness?

It's tricky to pinpoint a specific spot; sometimes it's just a general degradation of the cable due to heat and vibration. Honestly, if you're not seeing anything obvious, it might be worth taking it to a trusted mechanic. They can properly diagnose the issue and replace the sensor or repair the wiring as needed. It's much better than chasing ghosts and making things worse. Cost me 95€ to get sorted.

Thanks for the advice! I took your suggestion and had it checked by a professional. Turns out, it was indeed a defective connection to the knock sensor. They fixed the wiring, and now everything seems to be running smoothly again.