If the light on the key fob still lights up, place the key in the ignition and turn the key to notch two and within 30 seconds press both the buttons on the fob at the same time, the doors should lock then unlock synchronizing the key to the central locking....... If light does not work on key fob you can get a new battery from any car shop and resynchronise the key as above .
hope this helps
paul, April 2006