Hi, Yes this subject has been covered hundreds if not thousands of times. I have searched but cant find a answer specifically to this question.

What exactly is programmed to the immobilizer to match?

Immobilizer
Key FOB
DME?
Alarm Control Unit?
Any other Steering column computer or locks?

 

"What exactly is programmed to the immobilizer to match?"

The immobilizer stores the key FOB (up to 4) code number.
When the FOB is activated, it transmits that code which is received
by the immobilizer. If that code matches the stored code, the immobilizer
then transmits (wired) another code to the DME ECM to allow starting.

 

so is the DME programmed to the immobilizer? or it just gives signals to it.
My point is if I change the immobilizer with a matching FOB into my car will it start?
or does the DME have to match the immobilizer as the FOB does?