Strange problem that started happening AFTER the dealer changed my reverse beep pattern to single beep. Not sure if that has anything to do with my question, but I did notice that after they did that my FM presets were gone which might indicate a complete reset of the car? Who knows... My audio doesn't seem to remember which last input (FM, CD, USB...) I was using before the last shut off. For instance, say I was listening to a CD and turn off the car and when I turn the car back on, the audio is either OFF or sometimes it turns on at some FM preset or another audio input. Strange no? This happens all the time regardless if I was lasting using FM, CD, USB or whatever.
I had the reverse beep (and a bunch of other settings) changed during PDI before I took delivery, and in my V w/ nav, it always starts up on the audio input I was using when I turned the car off.
Same with my III with Nav, I had the reverse beep changed to one beep and have had no problem with the audio.
All right, then it must be something else not related to the reverse beep. Anyone else wanna take a shot at it?
This may not help and I have no good technical reason for suggesting it other than a complete power down sometimes fixes software glitches. If it were me I would disconnect one of the battery connectors, let it set for 5 or 10 minutes then hook it up again. All your audio presets will be gone and you can start from scratch and see what happens. I have had my battery unhooked (for other reasons) and it will not reset your customizable options, i.e. the reverse beep will still be at one beep, door lock/unlock options will not change etc. You should check the Nav system, the speeds may go back to default I don't remember for sure, but I think all my destinations were still there. If that don't fix it I would take it in and tell them your audio system is broke.
I am having the same issue with mine except for the streaming bluetooth. If its on btooth, it will go back to that, even if my iPad is not in the car. If i'm on ipod through USB, it will revert to either FM or btooth. Did the OP ever fix this with battery unhook?