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:

    Automatic Headlamp System
    When it is dark enough outside, the headlamps come on automatically. Do not cover the light sensor on top of the instrument panel or the headlamps will come on when they are not needed. The syst ...

    Tire Messages
    TIRE LOW ADD AIR TO TIRE On vehicles with the Tire Pressure Monitor System (TPMS), this message displays when the pressure in one or more of the vehicle's tires is low. This message also displays LE ...

    Shifting Out of Neutral
    To shift the transfer case out of N (Neutral) do the following: 1. Set the parking brake and apply the regular brake pedal. 2. Turn the ignition to ON/RUN with the engine off, and shift the transmis ...