CCC - audio coming on and off randomly

[naxiu]

Hello!

I am a fresh owner of a 2007 M3 E92 imported from Japan and after a few days of driving and enjoying the hell out of it, randomly the speakers started playing music all of the sudden - then I realized I haven't even noticed it was supposed to be playing music all this time

So after it started playing for the first time, I drove for another 5km and turned the car off thinking it's all good. Came back to the car after an hour, starting it up and again - no audio at all (no music, no gong, no PDC etc.), no matter what source I am choosing. The CCC is all responsive and reacts to muting/unmuting by showing the icon, I can see the CD is playing back on the screen, but there is no sound. Again, driving for a while, I am not touching anything radio related and it randomly starts playing again when I am coming to a stop at a traffic light. Few seconds, it sort of smoothly changes it's volume (no, it's not the Adjust volume by speed function, I turned it off), but also lowers it as far as to a mute state, sometimes the volume changes between the speakers too (sometimes I hear the music on the right side for a second, then just the front etc), and then again after some time comes back again. I don't think I have heard like a very sudden cut yet, it's usually smooth, no glitches or weird buzzing sounds. When it plays music it sometimes even 'flows' between the speakers like I can hear a smooth transition from the rear to the front left and then front right.

I have tried researching this issue already and found some tips regarding water in the trunk but I don't think I have found anything worrying anywhere. I just took a look in the area of the CD changer and the amp below it but there were no obvious signs of any water/wetness at all. The combox (I think it is in the middle of the trunk floor?) was also looking alright with no obvious sign of damage.


Could it be maybe caused by drained car battery (just checked the date on the negative and I think it says 20 / 20 so in theory it's around 4 years old)? It has no issues starting up but maybe it's acting funny after the few months with battery disconnected on the ship? Any other tips?

Thanks for any pointers! I think I am gonna drop the car off to some audio magician but maybe I can try to narrow down the issue myself.

[naxiu]

Small update, got the battery tested at local shop:

Car off, 12,42v / 758en (nominal 850), "health" level: 89%, charge level: 60%, so I assume I can skip the battery and move onto the actual audio setup

[naxiu]

Fixed it all!

Replaced original E92 HiFi amplifier with one coming from E83 X3 - audio came back immediately, but the left door speaker was wheezing (or whatever the word is, it had noise over bass) - replaced it with a used one and it all works great now.