There is nothing wrong with the central locking, the key just needs programming to the RCL module.

To do this:
1/ Turn the ignition from position I and Position II (dash lights on) 4 times within 6 seconds, returning it to Position I (not OFF)

2/ Within 10 seconds, press and hold one of the remote keys until you hear a beep.

3/ Once all keys are programmed, start the car or wait 15 seconds.