lungs said...i had to get another key for our 2002 au falcon, had to purchase key from the ford dealership, take it to a locksmith/key cutter to get it to open the door, but not start the car, supposedly take back to ford after it was cut to have it programmed to start the car. the mechanic that services the car said he could program it but only succeeded to program new one but also deprogramed old one, he is still scratching his head,he also did something to the stereo so had to take proof of ownership to ford to get a code to make the stereo work again(that was free,the key saga is charged at every step) anyway still haven' been to ford to get the old key reprogrammed.

bring back my old hq ute,didn't even need a key for that

what i have learn't.... when buying a nused car ask for 2 keys
I have an AU falcon as well. The keys themselves have a chip in them that needs to be coded to the car or programmed as a copy. If you have two keys already you can code a new one to the car. If you don't have two, then you can go to a locksmith and have them copy the code onto a new key. I did this recently.
The remotes are different again, and you can program any AU series II or III remote to suit your car, but you need to have them all with you as you do this, otherwise the ones that are not present get removed/locked out.
You can get a key cut without coding it to the car. I haven't tried this, but I suspect it will open the door and the boot/tailgate. If its like my car, it would set of the alarm straight away anyway once you open the door without using the remote.