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:

    Daytime Running Lamps (DRL)
    Daytime Running Lamps (DRL) can make it easier for others to see the front of your vehicle during the day. DRL can be helpful in many different driving conditions, but they can be especially helpf ...

    Brake Fluid
    The brake master cylinder reservoir is filled with DOT 3 brake fluid. See Engine Compartment Overview for the location of the reservoir. There are only two reasons why the brake fluid level ...

    Tire Messages
    TIRE PRESSURE LOW ADD AIR TO TIRE On vehicles with the Tire Pressure Monitor System (TPMS), this message displays when the pressure in one or more of the vehicle's tires is low. The low ti ...