Mark P

2 DTCs Found:
17547 - Long Term Fuel Trim Add.Fuel:Bank2 System too Rich
35-00 - -
17545 - Long Term Fuel Trim Add.Fuel (Bank 1) System too Rich
35-00 - -


What would cause these DTCs?

DarinS4Turbo

Mark, did you change out your MAF yet? I recall it looked pretty dead in post a few weeks ago.

Mark P

the part is now warrantied by Audi, so if it was faulty it'll be replaced. I just want to be sure that there's nothing else that could be the cause. I might try my MAF in a buddy's car so we see if he gets the same symptoms. That should be conclusive. Odd though that now I've had two Hitachi MAF failures, since I don't know anyone else with even 1 failure. Nothing had changed in my car for 10months/35k miles before the 1st failure, and nothing at all changed in this last month, so perhaps it's just a coincidence that the replacement failed.

someone else mentioned that since the Hitachi reads 5V->0V instead of 0V->5V, perhaps that accounts for when they fail that the car ends up running rich instead of lean (which I believe is what others are seeing when their MAFs go, right?)

Kirk

... and the rich code then turned into an over boost code. New n75 valve solved the overboost. I often wondered if the rich code was caused by the n75 valve.

Might be worth a check of the n75 valve.

The other thing to check are the heated O2 sensors.

Kirk