key fob broke ?

If you can transfer all the internals from your old key to the replacement you'll be OK.
If you have to use the replacement key's circuit board it will have to be re-programmed using diagnostics such as tech-2, vaux-com, Op-com etc.

You will also need the security code from your Car Pass card to reprogramme.

The "ignition on, press the button" method will only re-synchronise a remote which is already programmed to your car.
The immobiliser chip can only be programmed once, so a second hand chip from another car can not have its code changed to match your car.

terrrry
November 2010