Ford Repair Questions? Ask a Mechanic for Answers ASAP
Is the red theft light flashing rapidly when you try to start the vehicle?
Did this happen after you replaced the vehicle battery?
And it does it for both keys for the vehicle?
You have a problem with the PATS key system. Since it happening to both keys, more than likely it is the PATS transponder which is mounted on the steering column around the ignition key cylinder.
You will need to take the trim panels off the steering column to access the PATS transonder. See below.