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:

    How to Check Automatic Transmission Fluid
    It is not necessary to check the transmission fluid level. A transmission fluid leak is the only reason for fluid loss. If a leak occurs, take the vehicle to your dealer and have it repaired as so ...

    Roadside Assistance Program
    U.S.: 1-888-881-3302 TTY Users (U.S.): 1-888-889-2438 Canada: 1-800-268-6800 Mexico: 01-800-466-0801 As the owner of a new GMC, you are automatically enrolled in the Roadside Assistance program. ...

    Passenger Sensing System
    The passenger sensing system, if equipped, turns off the front outboard passenger frontal airbag under certain conditions. No other airbag is affected by the passenger sensing system. If the vehicle ...