Some time ago, I posted about a similar problem with my '95 coupe. Finally broke down and bought a new fob, and after programming the new fob, everything was fine for quite sometime. Then recently while driving the door locks cycled, and ever since the system has been just unreliable. I thought I would once again reprogram the fob, but the system will not go into the programming mode; while trying to figure out what was going on, I left the key fob in the car and it locked itself with the keys and fob inside the car - fortunately, I could open it with the spare set of keys - so whatever you do,
do not leave the fob inside the car unattended!I then decided that this system just wasn't worth the trouble and removed the fuse in the PKE circuit and the car locked itself anyway!
I suspect the problem is with the circuit board that controls the system, but am not going to disassemble the dashboard to find out.
Keep the fob away from the car and just use the keys; if this is the only problem you have with your C4 (as it is with mine), I would suggest forgetting about this PKE system, which is just plain more annoying than it is worth.
Dave