[V6-12v] Service andCheck Engine Lights

Kent McLean kentmclean at mindspring.com
Sat Oct 28 12:12:46 EDT 2006

Casimiro Izquierdo wrote:
 > As you may recall, I changed the oil in my 2002 A6 2.7 Quattro a few 
weeks ago.
 > The "service" light came on at the time, maybe by coincidence.

You need to pull the diagnostic codes.  Some consumer auto parts stores
will test it for free -- they use their OBD-II reader to read the codes,
then hope to sell you the parts you need to fix the problem. Sometimes
the "Check Engine" light indicates the gas cap is loose (as that's tied
to the emission controls, it triggers as a problem), which should appear
right after filling the tank.

For about $100, you can buy a generic OBD-II reader to scan the codes
yourself. But it will just report the codes, and not tell you what
they mean when applied to your Audi.

A step up (in price and functionality) is either VAG-COM or ProDiag
testers, about $200. They are geared specifically to the VW/Audi line,
and give you better reports.

VAG-COM: http://www.ross-tech.com/
ProDiag: http://www.shadetreesoftware.com/

 > There is another issue, once the weather turned cold, 35 degrees for
 > a few days, the engine makes an awful noise when it starts cold.  It
 > is a very loud grinding, rasping, and shrieking sound.  If the car
 > is turned off and immediately started again, the sound does not come
 > back.

It could be the starter not releasing (or as you noted, the key not
releasing from "start" position). But it may also be the alternator
or AC compressor. A frozen alternator or AC compressor/clutch would
cause the belt to squeal like a stuck pig, but I don't think it
would magically unfreeze and disappear on a re-start.

Some morning, before the car is started the first time, I'd pop the
hood, and look at and listen to the alternator and AC compressor
while your wife starts the car.  It may become obvious what the
problem is. Does the '02 2.7 have a hydraulic PS pump? If so, watch
that, too.

Kent McLean
'94 100 S Avant, "Moody"
'89 200 TQ, "Bad Puppy" up in smoke

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