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:

    Fuel Gage
    When the ignition is on, the fuel gage tells you about how much fuel you have remaining. Here are four things that some owners ask about. None of these show a problem with your fuel gage: ...

    Engine Power Messages
    ENGINE POWER IS REDUCED This message displays when the vehicle's engine power is reduced. Reduced engine power can affect the vehicle's ability to accelerate. If this message is on, but t ...

    Headlamps
    The exterior lamps knob is located on your instrument panel to the left of the steering wheel. (Off): Turn the knob to this symbol and release it to turn off the Daytime Running Lamps (DRL ...