aTOMic

EDIT: I spoke to him just now and the dash lights DO come on... I apologize for wasting everyone's time with incorrect assertions

but in case anyone wants to read the original:

I could not find the cause of persistent lean codes so I took my car to an independent German car shop. It's been there 3 weeks. Today I hear from him that the battery went dead and "probably took out the authorize to start computer or the key recognition portion on the steering column".

Anyone ever heard of this happening? It was an old Bosch battery (9 yrs) and it has gone dead on me during extended periods of not using the car but always comes back when I used my smart charger. He said it checked out OK after charging.
Unfortunately his shop's almost an hour from me, I am extremely busy and car-poor, or I'd just go replace the battery and make sure he hasn't just lost his mind.
This guy's been working on VW/Audi for years and I really trust his knowledge. Sending the car to Audi Service would be pretty much a death sentence, since I'm pretty sure they'd find enough to exceed its value.

This is actually giving me chest pains. Help

tjf

I would put a new battery in 1st. If a battery is bad, it can cause strange problems. Being 9 years old, its more than overdue for replacement.

cstarky15

Man that sucks, They had the car for over a month and didn't find out what was wrong with it and then the battery is dead?
I would tell them to put in a new battery and see if it changes anything. Like said above having the battery low/dead causes these things to do very weird things.

aTOMic

Thanks, that's exactly what I told him and he said the battery checks out fine. If it wasn't an hour away I'd be on my way now I think... I hate to admit but this is so sickening I cannot think straight...
EDIT: I spoke to him just now and the dash lights DO come on... I apologize for wasting everyone's time with incorrect assertions
He explained that after inserting the key, the dash lights don't come on... major clue. He suspects the underseat module because of water intrusion which happened ~5 years ago. Just happened to flare up for the first time at his shop.

I can't even tow it home; no hitch plus it'd need flatbedding anyway... and then if it WAS either of those modules, dealer has to program them to the car (cannot be done with VCDS) and the got dammed dealer is al hour away, and has a bad reputation for honesty especially with older cars.

mishar

Dead battery won't make any weird problems. It is Art of engineering but not that crazy.

So new battery should work just fine. Problem with your mechanic can be the way he charged your battery, especially if he used one of those fast chargers. It wouldn't be the first case that they burn few modules that way.

On the lean matter, it could be vacuum leak, low fuel pressure, or clogged injectors.

Junius

When my 4.2 gave sporadic lean codes (with no symptoms), it turned out to be the right side fuel pump. Found this out after testing fuel pressure, in which I believe it was supposed to 52psi if I remember correctly and mine was down to 46, which is not terribly bad, but enough to throw intermittent lean codes every so often. Fixed it back in January, and has been code free since then.

Jack88

+1

Wouldn't be the first time. I've never heard of a dead battery taking out anything that putting a new battery in wouldn't fix. However, as Misha pointed out, there is some expensive damage that can result from improperly charging the battery in the car. If you use a fast charger or jump it wrong, you can take out a module or two pretty quick.

storka

+2
Everything is written to the chips in the kessy ecu and steering column
You could pull the battery out for a year and would still be ok
Something is damaged
You will probably have to take it to Audi to get a read on it
Or read up on how to get power to get a vcd read

When I stuffed up my keys there is a procedure to power up to get a read

It involves shorting some fuse or jumping some pins

Someone here may know or do a bit of a search

aTOMic

Thanks, Storka, I did find some helpful stuff searching your old posts. One guy who had immobilizer problems (05A8w12) didn't post the resolution so I pm'd him...

Using search on the Bentley cd I found there are two immo versions which need to be replaced after they're activated if I understand it correctly. Inside that black plastic box in front of the battery. Haven't searched for that yet... J655 "Battery Switch-off Relay". Joy. Prolly cheaper than the $1189 module under the seat (KESSY but D3 manual calls it something different).

aTOMic

SSP on the thing (p. 21). One version can be reset according to this, probably an oversight in the service cd