Hi I have a 98 A6 quattro with 2.8 with stock bose radio. Couldn't hook up to vag com because it was saying K1 short to ground. The transmission is now in fail safe mode. Please help with any advice. Thanks. Tried disconnecting abs took radio out. All fuses ok. Does anyone know how to get to TCM under carpet where exactly is it under the carpet on passenger side. Thanks for any advice

 

I just recently bought 2001 a6 with the v8 4.2 liter for cheap because it is in this fail safe mode, I did some research and found that one of the common problems with these cars is the ecm located under the passenger side carpet seems to get wet, electrical-wet not good. So I pulled up the carpet to check it out, it was really easy just 2 screws on a panel, pulled off the panel near the door at your feet and up pulled the carpet, and wow was I surprised with all the water under there, no kidding its a problem. So I put a dehydrator under there to dry, dried out ecm but it didn't work I will probably need to buy a new one, it was also really ca-roded.
I also have the v6 version of the car and it went into fail safe mode also, its acts different then the v8, the v6 just does't shift into final gear where as the v8 just stays in 3rd or fourth gear, im sure with the extra power, "fail safe" is extra precautionary. but ya same thing pulled up carpet and it is all wet under there, so I do the same dry it out, fixes nothing. So I em wondering if maybe it is fixed but the codes need to be cleared by a scan tool, I tryed disconnecting battery to clear the code and that didn't work.
If not all that then I'll have to track down elec. problem that may have been caused by the water.
Lets do some more collaborating and figure this out together