I figured Id ask in this thread as it seems there is some pretty knowledgeable people on this site. My 2004 e53 X5 has been retrofitted with TCU Early 2004 I believe and I was able to pair it successfully . It worked for three months and now it pairs but I have no audio. I was trying to decipher the wiring diagrams but does anyone know how the bluetooth gets its audio and from what wiring? I read somewhere that pin 6 and 12 off the small black connector off the radio module is what does it. Any ideas on how to fix this issue of no audio but bluetooth connects? I even coded the TCU to my car with NCS expert but it doesnt see the TCU in NAvcoder..pretty strange but Im not giving up.