OnStar Services

See also:

Checking Coolant
The vehicle must be on a level surface when checking the coolant level. The coolant level should be at or above the FULL COLD mark when the engine is cold. The coolant level should be above the ...

Exterior Lighting Battery Saver
If the exterior lamp button has been left on, the exterior lamps will turn off about 10 minutes after the ignition is turned to LOCK/OFF and a door has been opened. This protects against drainin ...

Service Only Mode
This power mode is available for service and diagnostics, and to verify the proper operation of the malfunction indicator lamp as may be required for emission inspection purposes. With the vehicle ...