Auto Lock

In this case it's functioning correctly. You shouldn't use the fob to lock the doors when you're in it because if you try to unlock from the inside the alarm will go off.

But if you do lock it from the inside with the fob and don't open the doors it will relock as if you were outside the truck, just like crashnburn said.

As for how you locked the fob inside the truck is beyond me. If I try to lock the doors with the handle sensor with the fob inside it beeps for a 5 seconds, just like the manual says.

 

HOW DO YOU TURN THIS feature off