Hi, I have a 2001 Audi TT. For quite some time my car has been misfiring, had a very poor fuel economy, rough idle, and loss of power.. the typical symptoms of a faulty MAF, so yesterday I replaced the MAF and all of those symptoms seem to have gone away.. GREAT! But now, when I accelerate quickly or place a moderate to high load on the engine, the turbo cuts out and the car goes limp for a brief second then kicks right back in.. pretty much like skipping.. I checked my DTC's and I am throwing a 17705 fault. I know there are a few causes, but I was wondering anyone had seen the most common or specific cause when this code is thrown? They say to check the Diverter Valve, however I find that a strong coincidence that it just decides to begin failing the same day I replace the MAF.. or is there some kind of correlation? I did a throttle body adaptation, thinking that the car may have become acclimated to the power distribution with the faulty MAF, but it really did not make a difference. Any and all of your knowledge and expertise is always appreciated.

Thanks!

 

when is the last time you changed your plugs? they may need replacing and the problem was just being masked by the bad MAF.

 

well about 40,000 miles ago.. but i pulled them a month ago and they looked fine. even got 3 or 4 opinions.. would that cause a 17705 fault (drop in turbo pressure) though? masked or unmasked? i mean, i thought of that as a possibility.. but the strange thing is when the MAF was bad, the pick-up/acceleration actually felt perfect if the car had a chance to warm up before take off.. it was just a little slower than normal. the turbo itself actually felt great. if i didnt let it warm up before take off then i would stumble & miss fire.. etc..

 

reset ecu (disconnect battery)
seafoam
spark plugs
boost/vac leakdown test

 

Exactly. Change the plugs and make sure they are re-gapped correctly. If this doesen't do it, look into coil packs.

 

i noticed you keep saying your turbo cuts out. do you have a boost gauge that you are watching in real time or are you just presuming the loss of power is from the turbo "cutting out"?
remember the turbo has momentum. if you lost pressure suddenly like a surging it would be because your DV is venting for some reason. this could be caused by a small vac leak and if you don't have a boost gauge you should still hear it vent. also you might hear a hissing under boost from the side of your air intake. that's because the DV cannot close all the way.
generally surging power delivery is caused by bad plugs or coils especially when it occurs with a flashing CEL that goes away after a few seconds.
40000 miles on the same plugs is means its probably time to replace them. look at the FAQ for recommendations on plug types.

 

thanks everybody so far! ninja, well i feel it and i VAGed it. i got very sporadic readings.. at times i would get values well under requested boost and others values well over requested boost. i checked the plugs about a month ago.. as regular maintenance.. looked fine, like i said, i also got 3 or 4 opinions.. i have the top of the line plugs PFR6q's.. i thought those were rated for 100,000 (obviously i wouldnt wait that long), but i really dont drive the car that hard.. i was wondering by chance, if i POSSIBLY got a bad MAF, or maybe it was damaged during shipping? i mean its a genuine OEM bosch.. or would that throw an additional code relating to the MAF? the only code i get is 17705.

thanks!

 

It's your plugs. Get new ones and re-gap them. The gap's may have not been perfect to start with on your current plugs and now they are worn and the spark blows out as the boost builds. No spark=miss=loss of power=check engine light. It's that simple.

If you have a vag and think you have received a bad replacement maf, why would you just test it? 175g/s at WOT is correct. I'm sure your maf is fine though.

 

From Ross-tech 17705 code
Possible Symptoms
Power Loss
Possible Causes
Leaking hoses and/or pipes between components
Check Boost Pressure Control Valve (N249) it should ohm @ 25-33
Possible Solutions
Check hoses and/or pipes between components
Check / Replace Boost Pressure Control Valve (N249)
Check / clean Throttle Valve, do Throttle Body Alignment

 

The thing is im not even getting a Check Engine Light.. just that single code.. but I was going to do some tests today including misfire count and MAF with the VAG but didnt get the chance, so hopefully tomorrow. Im still wondering though how does anybody attribute the fact this happened the same exact day I replaced my MAF? Can the plugs not handle the new MAF? Why wasnt I getting these symptoms with my old faulty MAF?