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:

    Engine Coolant Temperature Gauge
    Metric English This gauge measures the temperature of the vehicle's engine. If the indicator needle moves to the hot side of the gauge toward the colored line, the engine is too hot. If ...

    When to Check Power Steering Fluid
    It is not necessary to regularly check power steering fluid unless you suspect there is a leak in the system or you hear an unusual noise. A fluid loss in this system could indicate a problem. Have th ...

    Active Fuel Management®
    Vehicles with V8 engines may have Active Fuel Management™. This system allows the engine to operate on either all or half of its cylinders, depending on the driving conditions. When less power is r ...