kevin880

I am hoping someone can answer 2 questions on this problem. I had a check engine light after a fill up so I assumed it was a loose cap. I checked but everything was okay. 2 days later I went to the dealer and they said I had a bad knock sensor and placed the part on order. The following day I filled up again and the light went off. It stayed off for 4 days and then came on again. After cancelling I have made another appointment to have the sensor replaced but I am still concerned that:
1. Would a sensor go bad and then correct itself for the light to go out?
2. When I close my gas cap I have no clicking sound it just feels like it hits a stop. Is that normal?
I really hate the idea of them taking the heads off to replace this part and then find out it wasn't even that in the first place.

gronk

Might be a dumb question but what brand and octane gas are you filling up with?

in2dwww

Same issue with an S6 recently:
https://www.audiworld.com/forums/sho....php?t=2863827

tenspeed

I would have the sensor replaced. I don't think that the heads would have to be removed to replace it. They are generally bolted to the engine block somewhere.

Have the dealer check out that gas cap when the car is in for service.