Re: ECU Failing on 20v CQT??

[quk@isham-research.demon.co.uk (Phil Payne)]

In message <3.0.3.16.19990407082208.21a7590e@n-jcenter.com> Mike Arman writes:

> If the ECU is reluctant to save the settings, this sounds very much to me
> like a failing EPROM - this sometimes happens with EPROMS in computer
> BIOS'es - replacing the chip solves the problem (although most of the time
> it is the CMOS battery that's bad).

If the EPROM fails, the ECU is toast.  It's possible for a minor storage
error to occur, but this will always produce the infamous error code
"1111".

It keeps its "settings" - so far as these exist - in RAM.  Things like
the current ignition timing for each cylinder, etc.   In early ECUs,
this RAM is volatile - in the later ones it's not.  Perhaps our
wrench friend was trying to dump codes after the ignition had been
switched off - assuming the memory was permanent when it's actually
volatile on this car.

I suspect this car has an intermittent or borderline problem that is
beyond the wrench's competence.  In such cases, a damn good read of
Scott's web site always prepares you for the next conversation you
have with the guy.  Very, very few understand how important the
electronics is - in a very real sense, post-1987 Audis are computers
with engines wrapped around them.

--
 Phil Payne
 Phone: 0385 302803   Fax: 01536 723021
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