Won’t doing that give a code reading for the time it is disconnected?
If so, the next time the truck is in the company shop they will wonder why the code shows up when you have the truck but not when it is in the shop.
Assuming you plugged it back in before you brought it in.
Tampering with company equipment will get you fired pretty quickly. No warnings.
And the high idle time is a dead giveaway.
I can cheat my ’17 Cascadia for 30 minutes by wedging my tire thumper between the seat and throttle.
Give it just enough to barely raise the idle, as too much has little effect.