a8 snob

RE: 2004 a8L 175K

Parked car in garage and next day it would only fire for 2sec., this occurred 3 times then no crank and dash was dark. No lights at all. On key turn the MMI and other systems do not act the same and air compressor ran on acc.

Towed to local shop with ross tech and he could not access anything.

Towed to dealer 200 miles away and they said that their equipment could not access ANY modules or diagnostics at all. They want to spend at least a day on itto try to figure out what is what.

Not sure if anyone has had this problem of no start, dark dash (no lights), no crank, and no diagnostic access to control modules.

It is still at the dealer in Colorado with a HOLD ao any work until I figure out what is what.

Any questions or suggestions would be great. Dealer is stumped and mechanic is actually a friend.

Thanks,

Former A8 snob

BASARAB

As stupid as it sounds, hows your battery?

jakematic

Sounds like a dead battery to me too at initial glance.

Mister Bally has a thread about starter causing battery drain - can be felt by warmth.
Unfortunately search is offline at the moment...

Possibilities include crank position sensor and immobilizer, but access to modules has to be first to diagnose the rest.

If battery voltage is good and supplied to the rest of the vehicle, the first thing I'd do is use a fuse tester to check the major ones including the DLC (OBD port) fuse.
We had a BMW once that would constantly blow DLC fuse due to abraded wires.

Since the compressor ran it seems unlikely the battery interrupt igniter was triggered.
Could also be the battery management module.

MP4.2+6.0

+1 or 2

a8 snob

The car is at the dealer and yes the battery was NEW and load tested as it was theirs. Basically the car is dead at many areas including OBD port, dash, and other areas after a morning no start. I am afraid to have the dealer continue at $130 as hour and hope to tow it home and repair somehow.

Again, it has NO communication with the OBD port using audi diag., tool. I will suggest the attached quote as a possible fix and also search for other info. If a crank position sensor goes does that render the OBD port faulty?

Will look into all ideas presented and have an open mind as well.

BASARAB

No, it does not. Are any of your lights working in the car? Maybe battery connector is loose or smth like that.

a8 snob

BASARAB,

So far two highly trained technicians have looked at the car and shook their heads as to the problem. The car does have power to certain items, but none to others as pointed out. My thoughts my conclude with the fact that somewhere their is a short that does not let power come into the OBD system and also other systems. Basically a loose or broken wire somehwhere or possibly a control module (battery?) that is bad. The problem is how do you determine the module/short with no power to the OBD port.

It may be that the car will be scraped, but it would be great to try to figure it out somehow.

By the way, all the fuses are OK, and the battery and links are OK.

Thanks

Former A8 Snob

jakematic

Worse than the hourly rate, they may start throwing parts at it until it starts working properly...

a8 snob

Jakematic,

Thanks,

Not headed there yet at all, the dealer will not fix it as it is too risky. Where do you start?

I have some great info here and will get it back in my garage and attempt to fix it but it looks as though it might be parts on e-bay.

Was a great car while it lasted, maybe a miracle will get her runnin' again.

a8 snob

Dear Audi World:

I will offer a free prize of $250 mailed to you if you can correctly diagnose the problem. Please submit your entry and when I get the car back I will try them all and declare the winner. If you are partially correct you may be able to collect a partial payment.

Thanks,

Former snob