See also:

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 Advisor. T ...

Starting the Engine
If the vehicle has a diesel engine, see the Duramax diesel supplement for more information. If the vehicle is a hybrid, see the hybrid supplement for more information. Notice: Do not try to shift to ...

Four-Wheel Drive
If the vehicle has Four-Wheel Drive, you can send the engine's driving power to all four wheels for extra traction. ...