Passive Anti-Theft System (PATS) Operation
WARNING: This page is about a different car, the 2014 Ford F-150. However, it is still accessible from the selected car via links, so may be relevant.
PATS prevents the engine from starting by disabling the starter relay and fuel injector operation. If an unprogrammed key is used or if there is a PATS system concern, STARTING SYSTEM FAULT is displayed in the message center and the engine does not start. PATS cannot disable an already running engine.