It is better not to park with the vehicle running. If the vehicle is left while running, follow the proper steps to be sure the vehicle will not move and there is adequate ventilation.
See Shifting Into Park and Engine Exhaust.
If the vehicle is left parked while running and the Remote Keyless Entry (RKE) transmitter is outside the vehicle, the vehicle will turn off after one hour. If the vehicle is left parked while running and the RKE transmitter is inside, the vehicle will turn off after two hours.
The timer will reset if the vehicle is taken out of P (Park) while it is running.
Shifting out of Park
Engine Exhaust#07-08-49-020H: IPC Odometer Programming Method Quick Reference Guide - (Jun 5, 2013) Gauges Odometer
Subject:IPC Odometer Programming Method Quick Reference GuideModels: 2003-2014 GM Passenger Cars and TrucksAttention: This bulletin applies to vehicles sold in the U.S. and Canada Only.This bulletin is being revised to add the 2014 model year and update model list. Pleasediscard Corporate Bulletin ...