I have a C4 GP '10' reg with which I got the inbuilt Bluetooth system which had been working fantastically up until a few months ago. Then it started doing a few odd things like not making the call until the third attempt (this eventually sorted itself out) and not allowing you to look at the caller list (the contact list was always available) - sometimes it was non-selectable, sometimes it didn't show at all and other times it looked selectable but wouldn't let you select it. However, I worked around this, but realising my warranty expires today (13th) I mentioned it to the dealer who said it might be a problem with the phone but they would put in a new Trojan(?) unit which is often the problem.
Upon collecting the car they said they hadn't had any problems connecting to the Bluetooth before or after replacing it but hadn't tried with my phone, a Samsung Galaxy S2. So optimistically I got in the car and found that it was actually worse than before. It paired okay but wouldn't let me access my call logs nor my contact list so I couldn't make any calls at all. If the options were visible they were non-selectable but more often aren't displayed at all. They showed me the system working with a Blackberry but it still wouldn't do anything with my S2. I tried clearing the data in the Bluetooth software, unpairing and repairing, restarting my phone, using a third party Bluetooth file transfer program but to no avail. I received one call on the way home which worked and I did manage to get it to play music through my stereo but by starting it on the phone rather than through the car's controls but I can't make any outgoing calls at all.
A while ago I updated the phone's firmware to ice cream sandwich but I'm pretty sure the phone linked up okay after that and I really don't know why it would be worse now than when I dropped it in yesterday morning.
They also replaced the window control unit on the driver's door because I couldn't one touch close the passenger window from the driver's side but it's exactly the same as it was before. They've been very helpful and willing but I'm actually worse off than I was before.
If anyone has any ideas or experience of what to try to get the Bluetooth to link up correctly I would be extremely grateful.