Problems with the Theft of a Mustang 96

How are you all?
I have a Mustang 96 and the Theft flashes, it gives me a code on the 16 but I would like to know how I can check it or if someone tie the diagram of the anti -theft system, the car always starts with a key without a chip which makes me make that the problem could be the other (I do not know)
please

before hand I appreciate them a lot