Will old keys with immobilizer still work if PCM replaced?

[unclecane]

I have a 2012 Mazda5. My PCM is shot. If I replace with one I buy online. Will my old keys still work and with the immobilizer?

 

[hleboklop]

Here, this link might help: How to program PATS using FORScan v2.3.* - FORScan forum

(most probably, keys won't work)