Central locking won't work on my mk5 Astra?

Hi can anyone help my central locking on my mk5 Astra stopped working tried new battery in fob, resetting the key , disconnecting the battery . When I re connect the battery the door will lock and un lock with the fob once then am back to square one ( not working) had it on a diognostic no faults coming up been told could be the module ? Any help would be much appreciated thanks Dave