of VAG-COM and 200q20v's (part one)

[Dave Eaton]

brett,

how long did you let the car idle after you ran it?  if over 5 minutes have
elapsed, you need to re-run the car - the manual states "if the engine runs
at idle speed for a longer period, the specification may be exceeded without
an actual fault existing".

also, the actual value for display field 7 is amended in later 20vt manuals
(aby, aan) to be from 41-61.  as the isv hasn't changed, you are ok anyway.

if required, the isv should be checked 2 ways - static resistance across the
two terminals, and using the output tests of with the isv unbolted, and
checking to see whether there is any "stickiness" to the movement of the
rotary slide valve.  don't touch the slide valve - if looking a little
sticky or slow, you can clean it with carb cleaner which may help.

the static resistance should be 7.5 to 8.5 ohms.  later 20vt's (aby, aan)
specify a higher resistance for the same part, and allow up to 11 ohms.
this resistance is essentially temperature dependent, the higher the temp,
the higher the resistance.

hth,
dave
'95 rs2
'90 ur-q

-----Original Message-----
Date: Fri, 16 Feb 2001 23:35:35 -0500
To: quattro at audifans.com
From: Brett Dikeman <quattro at brettd.dsl.speakeasy.net>

Just got back; all values make sense and are, surprisingly, right smack in
the middle of ranges given.  All seems well.  No stored codes save the
usual car-isn't-started code, which I cleared while the car was
running; no codes came back.

Once exception was Channel 7, which was at 57.  Bently lists it as "Idle
stabilizer characteristic curve control", an "internal calculation
value."  This is one of 4 values related to idle control; all seemed
within range, including operating range, characteristic curve zero point,
and load adaptation.

What does this mean?  Well, acceptable tolerances are 47-55.  Over 55,
"air leakage problem; determine cause." Under 47, "Idle stabilizer valve,
see repair group 24."  Great.  Juuust great.  Do I interpret "57" as being
"just a teeny bit over, that's a minor leak", or do I see that as "off the
deep end, big honkin' leak"?