Fan problem origin found...finally
Thread Starter
Advanced
Joined: May 2001
Posts: 69
Likes: 0
From: Ida, Michigan, USA
Fan problem origin found...finally
I just wanted to let everyone know what I found out on my 94 fan problem. The check engine light would come on several seconds after I start the car. At the same time the fans would come on. I tried several times to check the codes by jumping the 4/12 pins but didn't get any codes. I checked a few sensors ( coolant temp, ac system) as well as the relays themselves and still couldn't figure it out. Luckily my employer decided to buy this Snap On vehicle diagnostic unit that adapts to EVERYTHING. Within 2 minutes with the diagnostic scanner running several tests it determined my knocksensors were bad. Crazy but true. Not sure why they failed or even how. I was suprised I didn't get a code with the on board check. Just wanted everyone to know in case they have a similar issue.
Drifting
Joined: Apr 1999
Posts: 1,261
Likes: 6
From: Middletown New Jersey
When the knock sensors failed, the ECM put you in limp home mode. This generally means that spark is retarded, fuel is added and the fans come on. The point is to keep you from blowing up your engine.
