I have been having the exact same problem with my C4GP 1.6 HDI Exclusive 2008 41k (bought only 5 weeks ago). It is due to go in to be looked at by a Citroen dealer (Arbury walsall) tomorrow. Lock the cable lengths with the ball-joint locking keys. N.B. : Check that you can shift through all the gears without running into any tight spots. Check that the movement of the gear lever is the same from front to back and from right to left; otherwise repeat the adjustment. Arfur Dent wrote:Yours is working correctly. The remote locks and unlocks all the doors and the boot. This is the usual way to lock/unlock the C3. The drivers door lock is a back up plan to the remote system in case the BSI has gone into deep sleep or the keys get out of sync. Hi folks Hit a bit of a snag with the wife's car. Had to disconnect the battery while doing some work on the car last week. After finishing the work I discovered a problem, which I can only assume is caused by incorrect disconnection of the battery, in turn causing a corruption of the BSI. The central locking works manualy with no problems, but i wanted to get it to work remotely. I brought a new battery for the key fob and still the central locking did not work. I  decided to follow some advice id seen while browsing the internet. 56WH.

citroen c4 picasso central locking problems