Replacing radio in a6, rear speakers don't work

SOURCE: Audi Concert problem

you must check wiring cable of left speaker-reconnect antenna cable and check if it is firmly connected and apply contact cleaner over faders.

SOURCE: 2000 Audi A6 Quattro Concert Radio

what do push on the radio to get the code to come up so i can enter my code in

SOURCE: rear speakers do not work with aftermarket stereo install

I had the same problem a while back after having a JVC MP£ player fitted at Halfords. The guy told me my sub-woofer behind the back seat wouldn't work with the new stereo which I said was ridiculous, then one of the other guys came to look and told him I needed a different cable to link everything together - then it worked brilliantly.
Sorry I dont know a part number but that is definately your problem.
I hope this helps - or better still that you already have it sorted !!

SOURCE: Retro fitted radio

i believe that car has a pre-amp in the rear speaker setup, but the clip should work fine, i would return it, they do have a 10 percent failure rate. Nothings wrong, there's just a lack of signal. If nothing else works you may have to run speaker wire from the deck to the rear. Its not bad, just takes some time and common sense, as long as you are comfortable doing that stuff, most of the platsic around where your doors go is simply clipped into place, and can be removed and replaced with relative ease, run the wires for both spkrs on the same side, get them in the trunk, and hook them direct to the speakers themselves. Good luck!

SOURCE: Hi I have an audi A6 (1998)and battery went flat

you can call any audi dealer and they can tell you the codes and how to do it for free here is a number for one 1 866 576 0107 in us.