We have a 2007 focus and have been having a long struggle with the remote locking. The main problem is that the key constantly disconnects. We've changed the key, changed fob batteries, this car had a new battery in the winter and the problem was there before this battery change. We've reprogrammed the keys many times but they always disconnect after a short while and now they won't program at all anymore. Has anyone got any idea what the problem could be? When they were just about working remotely the angle at which you could get it to unlock seemed to be very small. You needed to be in just the right spot. 

Thanks in advance for any help. 

Programming the keys is totally the wrong thing to do.

The module does not forget the key

This is possibly four issues:

1: The batteries you are buying for the fobs are cheap Chinese rubbish that don't have enough power to run. Ensure only genuine Energizer or Panasonics 2032s are used. Do not buy from Ebay etc

2: Early MK2s had the RKE receiver in the roof, directly behind the front interior lamp. The earth point rusts and it stops working, check for that, then check the functionality of the RKE receiver

3: Later Mk2s had the RKE receiver built into the BCM (Fusebox under glovebox), when the BCM starts going down, due to water ingress, the first thing that stops working is RKE. Check BCM for water ingress and replace if ness

4: The solder joints in the cluster are going down blocking the CAN signals, are you getting any other faults?

If any of your DTCs say "LOST COMMINICATIONS WITH......." or "THEFT DETECTED" then the cluster needs sending away for repair