Body Control Module (BCM)
WARNING: This page is about a different car, the 2013 Ford Explorer. However, it is still accessible from the selected car via links, so may be relevant.
The BCM is responsible for checking the identification from the PCM and checking the key in the ignition. It also controls the ignition states and determines the ignition mode or if the engine should be started depending upon input from the ignition switch.
If the BCM is replaced, at least two keys must be programmed and the parameter reset procedure must be performed to enable PATS .