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:

    What to Use
    WARNING: Adding only plain water to the cooling system can be dangerous. Plain water, or some other liquid such as alcohol, can boil before the proper coolant mixture will. The vehicle’s cool ...

    Lamp Messages
    AFL (Adaptive Forward Lighting) LAMPS NEED SERVICE This message displays when the Adaptive Forward Lighting (AFL) system is disabled and needs service. See your dealer. See Adaptive Forwa ...

    Power Steering Fluid
    See Engine Compartment Overview for information on the location of the power steering fluid reservoir. ...