Encoded Ignition Key
WARNING: This page is about a different car, the 2002 Ford Focus, 2001 Ford Focus, and 2000 Ford Focus. However, it is still accessible from the selected car via links, so may be relevant.
When ignition is in START or RUN position, PCM initiates the encoded ignition key interrogation process. Each encoded ignition key must be programmed into PCM before it can be used to start vehicle.