Fwd: [portlandaudiclub] Re: [Biturbos4] Help with a few fault codes

Michael Benno mbenno at yahoo.com
Thu Mar 3 19:26:59 EST 2005

Opps, I sent this to the wrong list

Michael Benno <mbenno at yahoo.com> wrote:To: portlandaudiclub at yahoogroups.com, Quincy Chiang 
From: Michael Benno 
Date: Thu, 3 Mar 2005 14:58:15 -0800 (PST)
Subject: [portlandaudiclub] Re: [Biturbos4] Help with a few fault codes


First are you chipped? 

You are absolutely correctly with you analysis of the engine fault code. I cannot address the radio code. I would suggest you search the radio code on the audiworld forums. 

The engine code is infact a boost leak, I would check/test the usual suspects, 1.TBB, 2. BBV, 3. F-hose, after that you can do a pressure test to see if there is leaks somewhere else (ego IC end caps, turbo cold side connections. 

Regarding the TBB, if you are not running the later or an upgraded version you may want to just as a matter of course. A stock replacement is less than $15. Make sure you get the revised clamps as well (I can give you the PN if needed). Look for cracks on the old one where the clamps go. 

Regarding the BBV you need to test with vacuum pump, they should hold vacuum for at least a couple of minutes. 

I can give you a hand if needed. 

Regarding your logging tests you should be using 3rd gear rather than 2nd gear for acceleration tests. 3rd gear gives you much longer sample times. The sampling rate fo VAG-com is a little slower so you will see greater deviations with smaller windows. You can take a look at my boost tests (also done in 2nd gear) <http://pictureposter.audiworld.com/14326/115-each-test.jpg> 

I had the same questions about lags between specified and actual boost. In 3rd gear these deviations are must less.
Mike Benno
a6 2.7t 6spd MTM1
Quincy Chiang <b5quattro at shaw.ca> wrote:
Hi everyone,

My car's been feeling slightly down on power lately, and the boost doesn't seem to be holding at 9 psi anymore (from boost gauge), more like 7-8 psi only. So I was doing some data logging last night with a borrowed VAG-COM, but the results were somewhat inclusive.

When I stomp on the gas in 1st of 2nd gear, the requested boost would shoot up and the acutal boost would lag by quite a bit and doesn't get to the requested level. But in 3rd gear, actual and requested boost seems to be on par. Didn't do any logging in 4th or higher gears as I didn't need a speeding ticket. I'll play around with it some more.

But here comes my question... while scanning for fault codes, I got the following two codes:

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

65535 - Internal Control Module Memory Error
00 - 00

Does anyone know what these are? I suspect the first one has something to do with my wierd boost behaviour. Thanks in advance for your help!!

'01.5 S4
'90 CoupeQ

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