spoon2000

My A6 is at the shop and the technician, who seems very competent, says he's unable to hook into the car's computer. He has checked and found no K Line voltage. His theory is that one of the modules is having trouble and shutting the whole system down (I have suggested that he start with the radio and then unhook the ABS module) but I'm also wondering if there could be a fuse or something that's blown. The car was jump started about a week ago, if that makes a difference to anyone. Factory radio still installed.

Thanks.

audifirst

check all the fuses at fuse panel, but I have feeling when your car was jump started it was connected wrong orginally,..which could damaged one or couple of your car components , I have seen that a lot lately, doing a lot of repairs, it is painstaking process now you need to disconnect each component and check if the connection can be made, usually either of the components are damaged they still will function but the diagnostics connection is damaged could be instrument cluster,radio,ECU, ABS, tranny ECU,

spoon2000

Thanks for this feedback. Turns out it was the radio (which is a factory Audi radio) that was causing the hang-up, and once that was disconnected from the car, the K Line came back up again. Very weird, as there's never been a problem before with the OBD or VAG computer.

The car didn't get jumped incorrectly or have the cables cross-connected -- I know because I'm the one who did it, and I went to extra lengths to make sure I was getting the polarity right since the battery is mounted backwards from what you'd normally expect and it was dark under the hood (I suspect Audi does this so the terminals aren't jammed up under the wipers, but it does make things a bit weird when jumping to have the battery backwards). But jumping inevitably involves a small bit of sparking when the last connection is made, and perhaps that's what caused the issue.

Peter Badore

If your radio goes into safe mode that may cause no communication with the scan tool. I experienced that on a 99 A6 Avant. After bring the radio out of safe mode the scan tool would connect to all the modules.

spoon2000

That's very interesting. It turns out the car battery was actually dead for several days before I jumped it, so perhaps that deprived the radio of power to the point that it thought it needed to shut down for anti-theft purposes.

I'll have to wait to get the car back from the shop to see what state the radio is in, because the mechanic told me on the phone that he just put the radio into the trunk after he pulled it to disconnect it to get the K Line running again (can't say I blame him for not wanting to fool with it once the computer came back up).

The card with the radio code is here at home with my the car's other paperwork, so it wouldn't have done him much good to reinstall it anyway, and it might have brought the whole mess crashing down again.

Peter Badore

I always write the radio code on the radio after I remove for service. Also, you
should check the the fuse on the back of the radio to make sure that it did not blow.

spoon2000

I'll check the radio fuse, thanks for that idea.

Writing the radio code on the radio kind of defeats the purpose of having a code, doesn't it? I'd rather keep the code with the car paperwork or at a minimum in the trunk so some crook can't get at it very easily. Not that Audi's radios were all that desirable in the first place, and not that they're even worth stealing at this point since most dealers have long since put their remaining replacement units on eBay to clear them out of the parts rooms...

Peter Badore

Of the hundred or so Audi cars that my friend's BMW dealership has seen
in the past few years only one car was missing a radio. The A4 and A6 radios
have an enlarged face so they don't fit other cars. Try getting the radio code for free when the code card is lost or misplaced on a weekend or a holiday or an evening. Check out the list of most frequently stolen cars--if any Audis are there it is probably the owners trying to get rid of them after paying someone to unsuccessfully repair their car. I love Audis but the repair cost and difficulty is punishingly high particularly for owners that do not fix their own cars.

spoon2000

Just for the collective knowledge base, it turns out that the problem was a blown 7.5 amp fuse on the back of the radio. If the radio was pulled from the dash, K Line worked. If the radio was installed with the blown fuse, there was no K Line communication with any modules. If the radio was installed with a good fuse in place, K Line communication with all modules was fine.

L Werick

Can u give some info...where is the instrument cluster connection?