Graywolff

I need advice I did a cardinal mistake on my Audi which I love.i had to jump start the car in a snow storm in -2 degrees cold. I could not see and hooked up the wrong leads and caused the terminals to melt
I quickly disconnect in 90 seconds
Car would jump start again but died in about two minutes
The car had been setting,not driven for one month in continuous below 5 degree cold .had it towed to garage to put new battery in and do a diagnostic. they were familiar with audis but were not a dedicated Audi repair shop
They put in new battery and it would start but they could not keep it running
They did a diagnostic and found that they could not communicate with the computer
They said that they could not communicate but they do not know if the computers were fried. They said that all the fuses were intact and not spent which confused them.i called the Audi dearer ship and they said that the electric surge could have burned out the alternator but that does not explain the lack of communication to computer.
They also said that it could be a burned out throttle body that will not let the car run.
The Audi dealership wants it towed for them to analyze it
I bought the car 10 years ago and have put $12000 into it as it had 145,000 miles on it
Input a used transmission in it with only 15 ,000 miles on at a cost of $6500
I really can not afford to put a lot more money into the car but it is an Audi and I can not afford a new one or used one
My family have long tried to encourage me to get rid of the car due to cost of repairs
The car is worth about $7500 in parts but a parts dealer will only offer $500 and the transmission is worth 6 times that.
I need advice as to what to do. Has anyone had any experience like this.could the computers be ok and something else does not allow communication

Sorry this is so long
I feel guilty of perhaps reducing this car to very little value due to my ignorant mistake
Audiworld member as of march 27 ,2014. Graywolff

omarcarbomb

When you say it starts but wont keep running.
does it stop running after 3 secs

If the little "car and key" icon continues to flash on the dashboard, this means that the anti-theft device (immobilizer) is active.

The A8 has over a dozen "computers" these modules as they are called are distributed throughout the car and connected to the "K-line"


Other than take out your modules and put them in a buddies same year A8 to test them you will need to communicate with them.

This shows you how to check K-line.

http://www.ross-tech.com/vag-com/aftermarket-radio.html

best guess I can come up with it that reverse voltage shorted the Immobilizer and the ECU is not getting the signal from the Immobilizer and shutting down.

This same short could be cause of not seeing modules.

This is a just a WAG.

Graywolff

Thank you the car runs for about 35 seconds and then quits

Graywolff

Omarcarbomb
I am new to the forum

I did not realize all the questions were from you
Wow I am so impressed with your knowledge
I will answer each question
1. Car and key icon. I do not know as the car is at repair shop

2.the A8 has dozen computer modules and distributed through out car to K line
I have no buddy A8 but I will show the repair man your link to check the k line
3. K line link. H
http:// www.ross-tech.com/aftermarket-radio.html

4.reverse voltage shorten the immobilizes and ECU is not getting signal from the immobilizes and is shutting down

5. The same short of immobilized may be the cause of not seeing the modulesagain I can not tell you how much I appreciate your knowledge
My repair man Alan is very good and perhaps he knows what you know but I will give him this message and have him try

Thank you again

theraudi1

Most likely you fried the ecu, maybe the main fuse for the dash and other fuses. Also, fuel relay or pump could be fried too. Where are you located? I have a "parts A8 4.2 '97" if you're local.