This happens a lot and is a common question on the forum, the number one cause is the fuse which Citroen have now changed from 10A to 15A. The second cause is the pump has packed up Or you've not had enough ant freeze in your washer bottle and the weather hasn't been warm enough to defrost the fluid in the bottle.
Firstly check the Central Locking Pump to make sure the hoses haven't come off. This is located in the very back right hand corner of the boot so you will need to remove the carpet and internal trim and you will see a block of sponge. Carefully lift the top off this and you will see the pump sat inside it.
If a door’s actuator fails, you will find that the door simply won’t open. Other doors on the car will most likely still open. Electric wiring issues: If you find that none of the doors open it’s often due to an issue with the central locking in general. It could be an electrical issue of some kind. Fault with the key fob:
K2Vg.