Starting is disable on 1998 Cadillac DeVille

I had a used PCM put in and programmed by dealer, I drove car home but after taking keys out of ignition and went back in and put keys in and it says "starting is disable antitheft " remove key"
so I put back the old PCM but still same problem, do you think my antitheft module is broken now??? or how an I reprogram the module to recognize my keys? can I do it myself or dealer?

1 answer
The most common caused for theft system problems are the wires running up the steering column to the ignition lock cylinder. I would recommend you have your theft system check by a qualified technician. If indeed the wiring is at fault the ignition lock cylinder will need to be replaced and new keys of the correct code for your car will need to be made.