2011 Silverado 1500 LTZ remote start?

[CarboneXVI]

Hey everybody. I own a 2011 Silverado 1500 LTZ, and in the glove box I have the RPO code AP8.

 

I purchased a Dorman 4 button fob included with an OBD2 programmer. I followed all of the steps to program, and the fob works with locking/unlocking. However, when trying to remote start, the blinkers flash like they saw the trigger, but the truck doesn't start. 

 

Being that I have AP8, what else do I need to do in order to make this work? My local dealer is asking for $330 for a new fob and programming (saying there is more involved than just programming a fob), but if this is something I can do myself with the right equipment, I'd like to think I can handle it.

 

Thanks.

[CamGTP]

I couldn't answer the programming question but I will say this, if the check engine light is on you won't get it to function.

[CarboneXVI]

I guess I should have added. My check engine light is not on, but my service light is on for the 4wd, and tmps sensor.