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:

    Antilock Brake System (ABS) Warning Light
    The ABS warning light comes on briefly when the ignition key is turned to ON/RUN. This is normal. If the light does not come on then, have it fixed so it will be ready to warn you if there is a pro ...

    Replacement Bulbs
    For replacement bulbs not listed here, contact your dealer. ...

    Tow/Haul Mode Light
    For vehicles with the Tow/Haul Mode feature, this light comes on when the Tow/Haul Mode has been activated. For more information, see Tow/Haul Mode on page 9‑42. ...