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:
Battery Load Management
The vehicle has Electric Power Management (EPM) that estimates the battery's
temperature and state of charge. It then adjusts the voltage for best performance
and extended life of the battery. ...
Potential Issues
Some OnStar services are disabled after five days. OnStar cannot perform Remote Door Unlock or Stolen Vehicle Assistance after the vehicle has been off continuously for five days. After five days, OnS ...
Engine Oil Messages
CHANGE ENGINE OIL SOON
This message displays when the engine oil needs to be changed. When you change
the engine oil, be sure to reset the Oil Life System. See Engine Oil Life System
on page 10&# ...