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:

    Grade Braking (6-Speed Automatic Transmission)
    The Grade Braking shift modes can be activated by pressing the button on the end of the shift control lever. While in Range Selection Mode, Grade Braking is deactivated allowing the driver to select ...

    Exterior
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    Engine Oil Additives/Engine Oil Flushes
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