This seems to be a popular subject :) . I've of course read the pinned thread at the top of the forum on reprogramming keys.
I received three keys with my car - two three-button keys and one two-button key. Only one key seemed to function remotely, which was one of the three-button keys, and this appears to be a master since the security light on the dash doesn't come on when I insert the key.
The two-button key was dead, no LED on the key when I pressed the buttons, so I assumed it had a flat battery and replaced it. Now, this key will start the engine fine, and the security light comes on on the dash briefly when the key is inserted into the ignition (although not when the key is turned, contrary to what's in the pinned thread), so I'm thinking it's not a master.
So it seems like my car has "forgotten" this key when it comes to the remote lock/unlocking and alarm, but is still remembered when it comes to the immobiliser.
My conclusion is that I need to go through the first bit of the reprogramming guide in the pinned thread, i.e. to make it work the remote locking again, but I shouldn't need to do the immobiliser bit again. Is this right ?
The other three button key is in the same state, i.e. it can start the engine but not lock/unlock the doors. Although it appears to be a master, since the security light doesn't come on when it's inserted into the ignition. So again it sounds like I need to do the first bit of reprogramming on this one too.
Have I got this right ? I realise the only way to really tell for sure is to try it, but I want to make sure I've not misunderstood before getting into that.