I need some help to diagnose the root cause of the bizarre things that are happening with operation
of the cabin electrics my 2003 Quattro Roadster. The story goes like this.

First the average fuel consumption started providing bizarre readings, jumping from 12 to 45
litres/hundred kms and then just rolling out wide ranging readings while the car was stationary with
the engine running. All other dashboard information is perfect, except distance to empty, which
varies with the reported average fuel consumption.

Next, the Bose audio decided it had lost power and went into safe mode. Since it was re-activated
with the security code, about a week ago, it has worked perfectly.

Most recently the auto feature of the passengers door window stopped working, both up and down. The
movement of the window was fine if the switch was held. This morning the auto feature was working
perfectly again.

All this time the average fuel consumption readings have continued to come from another planet. The
car runs perfectly and all other dashboard information, date and time, audio system information,
average speed, spot fuel consumption, etc., including the test function appear to be operating
normally.

I am concerned that a visit to the Audi Centre could result in a very expensive diagnostic effort
without actually identifying the real fault. All ideas gratefully received.

"Lester Burnham" <lester040 (AT) yahoo (DOT) co.uk> wrote

my only guess would be that all the problems are coincidental.

The fuel metering may be a sensor that's gone TU. Also those all electronic
panels have not got an excellent track record as they age.

dj
A4 1998 2.4 V6 SE with a fading instrument panel on warm ambient days...but
she's closing on 100K and runs every day like a dream.

Hi Lester,

On Sun, 27 Sep 2009 13:19:01 +1000, Lester Burnham
<lester040 (AT) yahoo (DOT) co.uk> wrote:

[Various electrical stuff]

How old is the battery?

I've seen a few Audis behave strangely (Airbag warning lights and many
more) with old batteries.

The BOSE and the loss of memory of the window switches points me to an
intermittent brownout of the electrical supply => Old battery.

Those batteries might still have enough juice to fire the engine but
for whatever reason the play havoc with the electronics.

Try a new one.

Regards

Wolfgang

Thanks Wolfgang, it is the original factory fitted German battery from 2003. Its longevity was the
subject of discussion only a few months ago. I will swap it out and see if that makes a difference.

Regards,

Lester

On Sun, 27 Sep 2009 11:00:12 +0200, Wolfgang Pawlinetz <w.pawlinetz (AT) a1 (DOT) net> wrote:

On Tue, 29 Sep 2009 08:18:02 +1000, Lester Burnham
<lester040 (AT) yahoo (DOT) co.uk> wrote:


Would be curious to hear from you what it was in the end.

Regards

Wolfgang

Wolfgang Pawlinetz wrote:
VCDS in case the convenience ECU is upset.

Well, it was all looking very fine this morning although it is still on the old old old battery at
the moment. I am just returned from a week away, without the TT, which was left on a trickle
charger. The battery was very low when I left. When I arrived home last night I swapped it to the
regular charger just to be sure the battery had every chance to be fully charged. This morning it
was 100% according to the lights on the charger. The car started easily and ran around town happily
with all systems functioning as Ingolstadt intended. Tomorrow when I have time I will stick the
volt meter on it to see where the battery is after standing for a day. However, I will get a new
one as soon as I have a moment regardless; 6 1/2 years is a good run for a battery... but it is
German.

Further (final?) update when I have the new battery.

Thank you all for the benefit of your experience and expertise.

__________________________________________________ _____________________________

On Sun, 27 Sep 2009 11:00:12 +0200, Wolfgang Pawlinetz <w.pawlinetz (AT) a1 (DOT) net> wrote:

Well, after a good charge the old battery was held up well and the bizarre behaviour of the digital
readouts, particularly average fuel consumption, stopped. Now with a new battery installed
everything remains fully operational and I trust it will remain so.

Thank you all again for your sharing your experience and expertise.

On Sun, 27 Sep 2009 13:19:01 +1000, Lester Burnham <lester040 (AT) yahoo (DOT) co.uk> wrote:

On Mon, 19 Oct 2009 06:10:26 GMT, Lester Burnham
<lester040 (AT) yahoo (DOT) co.uk> wrote:

Glad it worked out so easily.

Enjoy that fine car, Lester!

Regards

Wolfgang