MP4.2+6.0

as a preliminary note, many of you don't post a year with your description/complaint, and/or it's not in your signature. It helps if you do and want help, since the issues and fixes vary by year. As you will see in a minute, you should consult the TSB's when these come up as a source--Audi produced Technical Service Bulletins, which the shop tech's use similar to what I describe here. With the passage of time and later owners, various of the older ones are getting lost knowledge wise. And to anticipate, no I can't post them directly, and I don't even know how to. They are part of Bentley. Sometimes by Googling the numbers you can find a version of them on the web somewhere from prior experience. See below. These may help, but I didn't try to read all of them in the stereo area. From experience when I have an issue and vaguely remember I might have heard it before, I start going through TSB's and hope I might find one or more that fit.

For 2004-2006's with Bose (which should be all of them; B&0 was 2007 IIRC) and a Bose 4000 amplifier, a TSB describes symptoms as no audio from all sources as long as vehicle is cold--"customer may experience the following conditions after entering his vehicle in very cold weather conditions (-12C, 5F)". Goes on to say if you disconnect amplifier or drive a few minutes of warm up, it returns to normal. Also says MMI menu remains displayed. Can also lead to a screeching sound as another symptom, and may store DTC 01044 in module 47 --sound system. It says the underlying issue is internal voltage stabilization for the processor. The Bose 6000 amplifier (i.e. a rev.) fixed it. But it also says a software update is available. There are update CD's apparently, which depend on your amp part # and software version. TSB 91 08 112, aka 2016657/2. Here's a link I found to it searching the second #: http://uberlame.com/a6_tsb/Stereo/BO...0condition.pdf

For 2007's there is a second/different TSB that may read on this. Issue originates in the CD player--2007 is when they intro'ed the MP3 capable ones IIRC, and I guess the early ones had issues. TSB description is popping sound and sound dropouts in all audio sources. TSB 91 08 105, aka 2014972/3. It also says no fault codes are stored, and it specifically says "It may happen more often in cold conditions." The test is to bypass the CD player optically. If it works, then it's a component issue inside and needs a new player per the TSB. Here's a web version of it I found: http://workshop-manuals.com/audi/a8l...56/page_16797/

SeacoastA8

Thank you very much for the extremely informative post. Mine is in fact an '06 and that describes the conditions precisely. On a side note I've updated my signature to reflect the model year.