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:

    Dual Tire Rotation
    When the vehicle is new, or whenever a wheel, wheel bolt, or wheel nut is replaced, check the wheel nut torque after 160, 1 600, and 10 000 km (100, 1,000, and 6,000 mi) of driving. For proper torque ...

    Vehicle Overview
    GM says the Sierra 1500 Hybrid's gasoline V-8 and electric motors team up for an overall mileage improvement compared with the regular Sierra. The Sierra Hybrid is only available as a rear- or fou ...

    Erasing Speed Memory
    The cruise control set speed is erased from memory by pressing or if the ignition is turned off. ...