Hi, I have a 2003 audi a4 1.8, I had the check engine light come on, so I took it to the shop, turns out it was the coil pack bc they were recalled. 2 days after getting the car back the epc light turns on a their is a loss of power when I accelerate. I noticed it came on after I came outta the car wash. I turned off after about a day. Then a week later I went to the car wash again, and both epc and abs lights came on. Again a day later they were off and the car drove fine. I wanted to see If getting the car wet was a fluke so I took it to the car wash a 3rd time and now both check engine light and epc are on. When I originally took the car to the shop, the codes came back to a throttle pedal sensor, but when coils replaced , no codes came back. What do u think the problem may be, maf, ecu, throttle body? Or what?

 

Well it's def related to getting the car washed and it is happening after you had the coil packs replaced. The coil packs have a rubber seal that prevents moisure entering the spark plug chamber. I noticed that when I did my spark plugs the coil packs seated in when I pushed them back in place. Perhaps one or more of yours are not seated well enough. Try pushing them in and don't be afraid to push hard. If this doesn't work take it back to the dealership that replaced the packs and have them check them. It is a good practice to put a light coat of lithium grease on the rubber seal of the pack.

 

Old post but just in case anyone else has this issue, its your ECU box/cover, had the exact, literally the exact same thing happen to me. I would go through the car wash and my EPC, CEL and ABS light would come on, put my car in "limp mode" (no power) and It would come up as a throttle position sensor/switch voltage correlation D/E code. Instinctively, I ended up swapping my throttle body, simply knowing any TPS code has to do with the throttle body since its all one piece, and I still had the issue. Turns out, my ECU cover had a crack, and the water that gets in at the back of the hood by the windshield would seep inside the ECU box. It would last until it was given time to dry out. I did a temporary fix by taping the crack. If your ECU cover is fine, I would suggest removing it and checking the rubber seal that is all around the lid, and see if anything is wet inside.

Hope this helps anyone else in the future!

cheers!

Frank