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:

    Compass Recalibration
    This display allows for calibrating the compass. See Compass on page 5‑6 for more information. ...

    Passing
    More passing distance is needed when towing a trailer. The combination will not accelerate as quickly and is longer so it is necessary to go much farther beyond the passed vehicle before returning to ...

    Brake System Warning Light
    The vehicle brake system consists of two hydraulic circuits. If one circuit is not working, the remaining circuit can still work to stop the vehicle. For normal braking performance, both circuits ...