If your like me and have a e90/ e91 with pdc and constantly find yourself lowering your radio when parking in order to hear the pdc gong then I´ve got good news
I succesfully coded a "volume down" on the radio when pdc is activated and it's pretty simple.
This is what you do:
Use NCSEXPER to read your RAD2 (mine is BMW professional, no i-drive)module and then and change the following value:
nicht_aktiv to aktiv
recode and there you go.. radio mute when pdc is active