[Biturbos4] Help with a few fault codes

j y jimnetpa at yahoo.com
Thu Mar 3 18:34:25 EST 2005

Steve is dead on!
You have a MAJOR boost leak - u DON'T want to go WOT - under any circumstances - or - u will be buying NEW turbos (I assume that u still have the stock K03s) too. I've had this DTC before - check EVERYTHING that Steve suggested. You will need a lift to inspect lower IC hoses.
The sluggishness you that u experienced is called "limp mode". The ECU automatically scales back boost to avoid "overboost", as a result, the DTC that u observed is logged. You can clear that code with VAG - but it will imeediately return - unless u fix the problem. This is your car's way of SELF-PROTECTION - be thankful - that Audi built in this fail-safe mechanism. 
If you don't personally own a VAG - I suggest that u make the $300 investment. I did - it has paid off many more times than the price! Now, I have a clue what my S4 is doing from an ECU perspective.

Steven Lin <steven at juniper.net> wrote:
Quincy Chiang writes:

> Engine
> 17965 - Charge Pressure Control: Positive Deviation
> P1557 - 35 - 10 --- Intermittent

>From the research I did, there are many possible causes. You should
probably do a visual inspection of the TBB, BPVs, and IC hoses. It
seems that tears in the TBB or IC hoses can cause this DTC, as well as
a stuck BPV. A pressure-test of the intake can help find leaks.
There are instructions on audiworld.com to build one from Home Depot
parts, or you can buy the kit from awe-tuning.com.

A bad N75 valve or stuck turbo wastegate were also mentioned as
possible causes. Even a bad MAF has been blamed.

Good luck.

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