ive just had this problem, you can remove the small panel below the motor and use a pair of pliers to wind the motor back wards and forwards. The motor can be removed by taking out the 3 torx head bolts, try the roof switch when the motor is out to see if it runs. One of the most likely problems with the motor jamming is the 2 threaded rod thingies that pull the sunroof backwards and forwards, they can get jammed up with stuff especially if you park under a tree alot. It is an easy job to get the sunroof off the vehicle, remove the 2 little covers at the very back of the sunroof track, remove the motor and also the 2 little end pieces at the front of the sunroof(from the inside of the vehicle) you will now be able to push the sunroof straight back, make sure you have a friend to help you remove it from the back of the vehicle. Once you have it out of the vehicle you can clean all the runners and the 2 threaded rod things, citroen recommend replacing the 2 rods when removing them ( i got away with just cleaning them up and adding a little white grease ). After your clean up (if the motor still works) you can reassemble the roof, push it all the way back to the closed position and then replace the motor back into position, if all goes well you will be fixed.
good luck
D Campbell, April 2009
