See also:

Liftgate/Liftglass
CAUTION: It can be dangerous to drive with the liftgate or liftglass open because carbon monoxide (CO) gas can come into your vehicle. You cannot see or smell CO. It can cause unconsciousness ...

Ignition Transmission Lock Check
While parked, and with the parking brake set, try to turn the ignition to LOCK/OFF in each shift lever position. The ignition should turn to LOCK/OFF only when the shift lever is in P (Park). ...

OnStar Personal Identification Number (PIN)
A PIN is needed to access some of the OnStar services, like Remote Door Unlock and Stolen Vehicle Assistance. You will be prompted to change the PIN the first time when speaking with an Advi ...