Odd remote start issue

[CPZ5901]

So i recently purchased and had programmed kit #19154444 on my AP8 equipped Tahoe. Dealer tested and said everything worked fine. Went home and attempted to start vehicle and only got the lights to flash but no start. Something I noticed though when I attempt to start it is the CEL light comes on (with the Tahoe off) and clears when the truck is started via the key. I checked and remote start is enabled in the DIC. Scanned for codes and nothing shows up (nothing pending either). If i sit inside the truck and lock the doors and start it with the key fob it will sometimes start once and then when I cycle it,ill get the CEL light again. Ive replaced the fob battery so its not that. Ive noticed the range is extremely poor too,it will lock fine from a distance but the remote start wont even flash unless im quite close to the truck. From reading on here it sounds like the antenna for the RS is near the back of the truck. I do have pretty dark window tint from having my truck in AZ for a long time. Im sure im going to have to go back to the stealership,but was wondering if anyone else has ever seen anything like this.