Ford cars require different methods to program the keys, but most modern models require an owner to have two programmable keys. Insert the first key into the ignition, and turn it into the on position without starting the car. After five seconds, remove the key and insert the second key, turning the ignition to the off position. Once removed, the key is programmed to operate that vehicle and no other.
This method should work for most Ford cars made after 1998; this is when Ford began to use transponder chip keys, also known as Passive Anti-Theft System keys. These keys work by communicating with the car's computer via an antenna located around the ignition lock cylinder.
If the owner of a Ford vehicle has only one programmable key, he must seek the assistance of a locksmith or a Ford dealership to program an additional key for his vehicle. Failure to use the specially programmed keys for Ford vehicles results in the starter of the car being disabled. This feature is installed to protect the car against theft, because it cannot be started without the computer chip in the key and the computer chip in the car communicating with each other.