This may be known, but myself and my dad looked for a while for a solution to the auto shutoff in our 2021 Sierra 2500HD because he takes his dog with him everywhere. The solution for us is:
1: Put truck in Neutral
2: Activate parking brake
3: Get out and lock doors with fob
That’s it. Works until you run out of fuel. I hope this helps someone.
Here she is. Mods so far:
Amp power steps
5% tint w/70% on windshield
Husky x-act floor liners
Extang Trifecta folding tonneau
Rhino extreme bed liner
My lift, wheels, tires and exhaust should be in this week. Been waiting forever it seems. I will do a build thread when everything gets here.