Have just 'upgraded' from 6310i with Cark-91 and interface lead to E39 BMW. The previous set up worked perfectly, radio mute, sound through hi-fi, steering wheel controls, contacts list on sat nav screen etc., etc.
After the upgrade (new 6288 phone, new CA-55 cable, new CR-43 cradle all from the local Nokia shop, so are genuine!) now nothing at except except radio mute. No sound through hi fi, no charging, no contacts list, no steering wheel controls, nothing. Some 'upgrade'! In fact no sound at all unless I disconnect the speaker connection that has worked perfectly for the last 3 years. It will work with the standard Nokia supplied speaker for the Cark-91.
The Nokia website confirms that my new set up is all compatible with each of the components and the Cark-91.
Does anyone else have the same problem, and hopefully the solution!