Re: Bluetooth Telephone System
Depends on which particular batch of E90 your car is, some batches which come with USB/AUX-in functionalities has the module for Bluetooth phone. you just need to buy the microphone, Bluetooth antenna, some wirings and pins, then get the car coded for the function.
steering wheel button will allow you to pick up/end calls and call the last dialed number. phonebook from phone will by synced from your phone to the HU as well.
if your car comes with the BMW(Garmin) portable GPS, then that GPS wiring has to be removed from the HU's connectors else the Bluetooth sound will not be sent through the speakers.