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
    For vehicles with a sunroof, the sunroof only operates when the ignition is in ON/RUN or ACC/ ACCESSORY, or in Retained Accessory Power (RAP). See Retained Accessory Power (RAP)  for more i ...

    Navigation System
    If the vehicle has a navigation system, there is a separate Navigation System Manual that includes information on the radio, audio players, and navigation system. The navigation system provides detai ...

    Lamps
    Properly working headlamps, taillamps, and brake lamps are important to see and be seen on the road. • Signs that the headlamps need attention include dimming, failure to light, cracking, ...