I have a perplexing problem that has been haunting my 1994 850 Turbo Wagon for several years. The Check Engine light is on most of the time. My dealer always finds that the code indicates a bad Knock Sensor. The sensors have been replaced 3 times and the ECU 1 time without any change in the warning light behavior. The problem started a few months after purchasing the car new. The car was in an accident early in its life but the timing of the light is not directly matched to the accident (but close).

Although the car runs fine, I’m tired of looking a light that has become meaningless. Can anyone suggest a course of action other that removing the light bulb?

I looked through the archives and could not find anything that directly addressed my problem but I did see mention of wiring updates. I have also heard that grounding problems can cause weird behavior.

Thanx for your help.

Eric