I have a 2004 525D with the pop up display but not Idrive. I have the basic sound system I think as I have no AMP of any sort in the boot. I have no sound atall. No dongs, no warnings or no music. Can anyone help ? I have changed the MPM Box in the boot amd put in a second hand radio. All fuses are ok ? Trying to figure out do I have a CCC or logic 7 or what system I am running to try and sort the no sound problem. Thanks very much to anyone who could help me

 

I have a 2008 528i, about 3 years ago my radio messed up it only plays bass no treble and the door chime is gone. I tried diagnosing using an optic loop bypass but no success. Tried changing fuses, no success. Ive taken it to indy, they couldn't figure it out. Took it to BMW dealership, they were about to charge me $500 to diagnose and in the end they couldn't figure it out so they waved the charge. They said the next step would be to do "pin testing." Unfortunately this can lead to a possibly expensive ordeal (depending how much digging they have to do into this electrical issue) so I have no longer pursued it. I feel your struggle. I have been driving around with a bluetooth speaker *sheds tear*