Checking codes on 89 100Q

Phil Payne quattro at
Tue Aug 31 10:36:54 EDT 2004

The short trick is to use a fuse in the fuel pump relay like we do in the UK with the MB
engine, and then read the codes using a diode light pushed into the same contacts.  Simple and
quick, but beware the codes are reversed - the light is ON when a properly fitted check engine
light would be OFF.  So you're counting gaps rather than pulses.

Takes a while to get your head around it.

----- Original Message ----- 
From: <Stpndsmnn at>
To: <Quattro at>
Sent: Tuesday, August 31, 2004 4:25 PM
Subject: Checking codes on 89 100Q

> Hi,
> is there any way to check engine fault codes at home on my 89 100q?  The
> check engine light keeps coming on intermittently.  I've checked everything
> obvious and everything seems to be alright so I guess I need to get a little more in
> depth...
> Thanks for any help
> Matt Kramer
> _______________________________________________
> quattro mailing list
> quattro at

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