See also:

Theft-Deterrent Feature
THEFTLOCK® is designed to discourage theft of the vehicle’s radio by learning a portion of the Vehicle Identification Number (VIN). The radio does not operate if it is stolen or moved to a di ...

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 ...

Checking Engine Oil
It is a good idea to check the engine oil level at each fuel fill. In order to get an accurate reading, the oil must be warm and the vehicle must be on level ground. The engine oil dipstick handl ...