I ran into "key problem" with my car few days a go. The remote central locking stopped working and at first I put the blame on the battery in the key, so I changed the battery. That did not fix my problem and the remote central locking was still not working.
Now I really thought I was facing some expenses getting this fixed properly. But Internet to the rescue. After short search I found method that might be wort trying. Reprogramme the central locking.
Here are step by step instructions I found from The Car Key Man
1. Enter your car and leave the driver door open.
2. Turn the ignition key on and off three times (leave key in ignition)
3. Shut and open the door three times.
a. You should hear the lock cycle.
4. Press one of the button two times on your key.
a. You should hear the lock cycle.
b. Take your second key, if you have one, and press twice.
i. You should hear the lock cycle.
5. Turn the ignition on an off one time and take the key out.
The also have a demonstration video for this--Cheers