kjmiles

Hopefully someone can tell me if there is an electrical relationship in my issue or it's just something that hasn't been found yet in the cooling system. In my '03 1.8 A4 Avant, I've had a cooling fan issue on an off (mostly off) for about 2 years. Every now and then, the fans will come on at cold start up and stay on for anywhere between 6-7 minutes and longer - like 30 minutes. Eventually, the Check Engine Light comes on - maybe not when it happens right away, but maybe a few days later. I don't have overheating and have read other postings on the forum about similar issues. My mechanic (long time Audi/VW guy) replaced the 4 pin NTC temp sending unit last January, which was followed by more wild running fans, and then a month later that was followed by replacement of the temp sensor at the radiator outlet. I had it in again two months ago with the fan issue and a P2181 Cooling System Malfunction code, a P0300 misfire, and a P0301 Cylinder 1 misfire (probably unrelated). The fans stopped running when when they cleared the codes, but said that they might look at replacing the control module if it persists. They're on again a month and a half later.
I live in MA and it only seems to happen in the winter because it didn't happen at all during the spring and summer. Granted, this could be coincidence. Here's the crazy theory/coincidence that I had been thinking of (but feel free to tell me it's probably something else like the control module - and I had my TB and WP replaced about a year ago). I installed a Dension iPod module and wiring harness to my stock stereo last December. This was supplied by Enfig in NJ and I installed it step by step myself. Is there any chance that there's a connection between the two as I don't know what else, if anything, is running through that particular wiring? Like I said, feel free to slap me down and tell me it's just something in the cooling system. I just want it to stop.
Thanks,
KJ

lyleswk

Sounds like the fan module to me and don't think it has anything to do with the other work / codes.

kjmiles

Thanks for your opinion. What's the cost of having the fan module replaced? Forgot to say that when the fans come on, my timing doesn't advance - it is the normal warmed up idle even if the car has been sitting overnight. Of course, the last few days, the timing has been advancing as usual at start up and no cooling fans come on. So strange.
KJ

lyleswk

Not sure but would guess 300 to 400 dollars.

kjmiles

Would the fans coming on coincide with my check engine light coming on? I had some broken wires in my drivers door, but I guess it had nothing to do with my fan issue. Drat.

lyleswk

The answer as always is it depends. The only fault that would cause the fans to come on that I am aware of is a failed coolant sensor which I don't believe will cause a CEL. But, there might be something else I am not aware of that could. As always, get VAGCOM codes. And no, can't imagine anything in the door harness that would bew a player in fan or CEL.