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:

    Brake Fluid
    The brake master cylinder and, on manual transmission vehicles, the clutch hydraulic system use the same reservoir. See Engine Compartment Overview  for the location of the reservoir. The r ...

    Resuming a Set Speed
    If cruise control is set at a desired speed and the brakes are applied, this shuts off the cruise control. However, it does not need to be reset. Once your vehicle reaches a speed of about 40 km/h ...

    If No Steam Is Coming from the Engine Compartment
    If an engine overheat warning is displayed but no steam can be seen or heard, the problem might not be too serious. Sometimes the engine can get a little too hot when the vehicle: • Climb ...