I have an 04/04 build X5 with Assist. I noticed the Bluetooth antenna in the back. My TCU has a Bluetooth logo and PK. However, Bluetooth is disabled at the factory on pre 09/04 cars for some reason mine included. All the TEL button would say when pressed was "PHONE CONNECTED?" Using NCS expert, I coded the TCU to BT operation and BT_HANDSET to aktiv, and it immediately started working. Only annoying part is that is reverts to speaker when the other party picks up the phone. Might be an iPhone only problem but it only happens in the X5.