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:

    Speedometer
    The speedometer shows the vehicle's speed in either kilometers per hour (km/h) or miles per hour (mph). ...

    How to Check Power Steering Fluid
    Check the level after the vehicle has been driven for at least 20 minutes so the fluid is warm. To check the power steering fluid: 1. Turn the ignition to LOCK/OFF and let the engine compartme ...

    Engine Coolant Temperature Warning Light
    For eAssist vehicles, this light comes on briefly while starting the vehicle. If it does not, have the vehicle serviced by the dealer. If the system is working normally, the indicator lig ...