Engine Coolant Heater
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.
An internal thermostat in the plug-end of the cord may exist which will prevent engine coolant heater operation at temperatures above −18°C (0°F).
If the vehicle has a diesel engine, see the Duramax Diesel supplement for more information.
See also:
How to Check Power Steering Fluid
Notice: Extremely small amounts of contamination can cause steering system damage
and cause it to not work properly. Do not allow contaminants to contact the fluid
side of the reservoir cap/ dipst ...
Diagnostics
OnStar Vehicle Diagnostics will perform a vehicle check every month. It will check the engine, transmission, antilock brakes, and major vehicle systems. It also checks the tire pressures, if the vehic ...
Automatic Transmission Shift Lock Control Function Check
WARNING
When you are doing this inspection, the vehicle could move suddenly. If the vehicle moves, you or others could be injured.
1. Before starting this check, be sure there is enough room around ...