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 vehicle is equipped with the Tire Pressure Monitoring System. If a diagnostics check is needed between e-mails, push OnStar Additional Information , and an Advisor can run a check.

    See also:

    Air Conditioning
    (Air Conditioning): Press to turn the air conditioning on or off. An indicator light comes on. If the fan is turned off or the outside temperature falls below freezing, the air conditioning compr ...

    Braking
    See Brake System Warning Light. Braking action involves perception time and reaction time. Deciding to push the brake pedal is perception time. Actually doing it is reaction time. Average reacti ...

    Backing Up
    Hold the bottom of the steering wheel with one hand. Then, to move the trailer to the left, just move that hand to the left. To move the trailer to the right, move your hand to the right. Always b ...