Service Immobilzer light
 

I have a 2005 Pacifica 3.5L. It has an idatalink car starter. Last week my wife went to start the car in the morning and it wouldn't start. Service Immobilizer light was flashing. I disconnected the battery, after 20, I reconnected it and the car started. Next morning, same thing, except the one time it said invalid key fob. I did the disconnect/reconnect battery and it started again. Third day same thing happened and I did the same thing, then car turned off while driving and wouldn't it wouldn't reset when disconnecting the battery. We tried reprogramming keys at dealership, but it didn't work. They said we needed a new PCM. I bought a used one. Replaced it and it fired up right away. After I turned it off, it wouldn't start, said service immobilizer. Did the disconnect/reconnect the next 3 times to start it, now that trick don't work at all. I think something in my remote starter is has something to do with it. We have had the starter for 2 years no issue though. Any ideas?

Take it back where you got the remote starter installed and talk with the people there.