The engine heater can provide easier starting and better fuel economy during engine warm-up in cold weather conditions at or below -18°C (0°F). Vehicles with an engine heater should be plugged in at least four hours before starting.

It is shipped from the factory with a tie holding it in place. Use care in removing the tie so that the cord is not damaged.
Check the heater cord for damage. If it is damaged, do not use it. See your dealer for a replacement. Inspect the cord for damage yearly.
Warning
Improper use of the heater cord or an extension cord can damage the cord and may result in overheating and fire.
Failure to use the recommended extension cord in good operating condition, or using a damaged heater or extension cord, could make it overheat and cause a fire, property damage, electric shock, and injury.
Keep the cord away from any moving parts.
If you do not it could be damaged.
The length of time the heater should remain plugged in depends on several factors. Ask a dealer in the area where you will be parking the vehicle for the best advice on this.
Starting the Engine
Retained Accessory Power (RAP)OnStar Overview
Voice Command Button
Blue OnStar Button
Emergency Button
This vehicle may be equipped with a comprehensive, in-vehicle system that can
connect to a live OnStar Advisor for Emergency, Security, Navigation, Connection,
and Diagnostic Services. OnStar services may require a paid subscripti ...
Engine Overheating
The vehicle has an indicator to warn of the engine overheating. See Engine Coolant
Temperature Warning Light on page 5-18.
If the decision is made not to lift the hood when this warning appears, get service
help right away. See Roadside Assistance Program on page 13-5.
If the decision is made ...
Torque Lock (Automatic Transmission)
If you are parking on a hill and you do not shift the transmission into P (Park)
properly, the weight of the vehicle may put too much force on the parking pawl in
the transmission. You may find it difficult to pull the shift lever out of P (Park).
This is called “torque lock.” To prevent torque ...