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:

    Sunroof
    On vehicles with a sunroof, the switch is located on the overhead console. The sunroof only operates when the ignition is in ON/RUN or ACC/ ACCESSORY or in Retained Accessory Power (RAP). See Retai ...

    When to Check
    Check your tires once a month or more. Also, check the tire pressure of the spare tire. ...

    Heated Mirrors
    For vehicles with heated mirrors: (Rear Window Defogger): Press to heat the mirrors. See “Rear Window Defogger” under Automatic Climate Control System for more information. ...