2001 mustang Gt auto question

[A B4C Z]

My sister has a 2001 mustang GT. The Theft light comes on randomly and the car wont start. I assume it shuts the fuel pump off. In gm cars key cylidners are common for something of this type. Well i orderd one and see theres nothing to do with the theft system in the ingition cylinder. What detects the "key chip" on these things. I have to keys they will both do it so im assuming its not the keys and its something else. It just started acting up within the last month or so. Any help would be great.

[wikked]

Check the antenna/transceiver wire for the PATS in the steering column... doesn't make sense that two keys would just crap out all of a sudden.

or the EEC fuse under the hood could be blown (large yellow 20A).

[Stangman98]

I agree with checking the antenna/receiver. You also might need to take it to a Ford dealer and see if any of the inputs for the PATS system are throwing it. My stepmom's dad had the same issue and he had to take it to a Ford dealer and have the PATS system checked out.