MingBlu
Have a read on my story....your light may not be that serious an issue....anyways take a read.
I have a 1.8TQ car and at 19 months old the cars engine management light came on. Called audi assist out, they troubleshooted and said it was a common problem of a dirty throttle body. Under normal driving the car was fine...however ever since owning the car from 17 months old, occassionally especially in on off boost usually second gear demand situations it would loose all boost temporarily giving a real jerk to the car. Obviously when this happened i usually throttled off and then instantly back on again and power was there no problem.
The cleaning of the throttle body did not cure this, but cured the management light (running to rich issue). However another 16 months went by and car continued to occasionally exhibit this symptom of sudden low down boost loss (about 2500 rpm)....although this could happen in a straight line as much as a corner situation.
Now....(here's hopefully the interesting bit)...the management light recently came back on again...car was however as usual driving fine 99% of the time. I thought immediately throttle body again, but thanks to the help of pure, i borrowed a VAG-COM and looked for faults before i thought about doing anything.
The car had logged faults of boost loss and running rich(idle) issues. I left the car running for a week or so and the light went off but the faults were still stored. About 2 weeks ago now, i decided to properly investigate and i took my dbw throttle body actually off the car. Pipe side of the throttle buttefly was fairly clean, however induction side was reasonably dirty and actually around the seating of the throttle butterfly there was also a build up of blackness!
I cleaned all this out with carb cleaner and fully reassembled. Also at the same time i put a brand new standard paper filter back in and cleaned the air box housing of any other crap. The upshot is the car is running fine, and now fingers crossed, 2 weeks of running my intermittent boost problem has gone. I think audi assist, only cleaned the pipe side when they came out 16 months ago and not induction side, and now that i have FULLY cleaned it the ECU is getting all parameters correctly responding.
Since doing this fix (and thanks to HTC and foolish for their advice) i've logged MAF, several times, checked the lambda values, and also logged block 115 for boost. Everything is giving consistent figures, so i seem to have eliminated my DV, MAF (AMM), pipes and lambda sensors as being issues......everything seems to have boiled down to a dirty throttle body and a nice clean air supply!
I'm continuing to monitor the car for faults, but it seems like they've gone away and now when i give it some welly it pulls good and hard, better than its ever done in almost 2 years of ownership. I think throttle body cleaning, is something i might do yearly from now on, just to be fully on top of the situation.
HTH
