Passenger Door Cenrtal Locking Stopped Working

[white lancer]

BMW X5 3.0i Sport 2004 Auto

Hi

My central locking has stopped working on the passenger front door.

When I lock the car from the key fob all the other doors and the tailgate lock fine apart from the passenger front door. The same thing happens if I put the key into the drivers door lock and lock the car using the key. Everything else locks apart from the passenger front door.

I can lock the passenger front door by pushing the little button down and then unlock it by pulling on the inside door release handle.

Is there some sort of electrical control module inside the door which may be faulty?

Thanks for your help in advance