DS5 rough idle knock sensor

I'm pulling my hair out here. I've got a 2012 Citroen DS5 with a gasoline engine that's giving me fits. The check engine light is on, and she's burning way more fuel than usual. Plus, the engine is idling rough, like it's about to stall. I've done some digging and it seems like it might be a defective knock sensor. I've checked the wiring and the plug, and it all looks okay visually, but with 248003 km on the clock, who knows? Any ideas before I'm forced to throw money at it?

4 comment(s)

I had a similar issue with my DS5. Check engine light, rough idling, the whole shebang. I'd double-check that knock sensor wiring. It can be tricky. Have you tried cleaning the contacts?

Yeah, I did give the contacts a once-over with some contact cleaner, but maybe I wasn't thorough enough. Was your issue definitely the knock sensor, and what exactly was wrong with it? Was it just a bad connection, or did you have to replace the sensor itself?

For me it was the connection, the plug was defective. I'd take it to a workshop to have them check. You don't want to risk damaging your engine with incorrect ignition timing.

I appreciate the advice. It ended up being a corroded connector on the knock sensor wiring, just like you suspected. New connector and a bit of cleaning and she's running like a dream now. Grand total: 95€! Check engine light is gone and the mileage is back to normal. Cheers!

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