Gen6 facelift immobiliser
From Wiki
RESYNCING AND RESETING THE ALARM FOB
Resync
With all the doors closed and the key removed (doesn't matter if the doors are locked or not), press both buttons together and hold them down for two seconds.
Reset
Remove the battery from the fob, press the arm button down for at least ten seconds, then replace the battery and reassemble the fob. Now carry out the resync as above.