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 Power Messages
    ENGINE POWER IS REDUCED This message displays and a chime may sound when the cooling system temperature gets too hot and the engine further enters the engine coolant protection mode. See Engine Overh ...

    Checking the Fluid Level
    Prepare the vehicle as follows: 1. Park the vehicle on a level place. Keep the engine running. 2. With the parking brake applied, place the shift lever in P (Park). 3. With your foot on the brake p ...

    Fluids
    Proper fluid levels and approved fluids protect the vehicle’s systems and components. See Recommended Fluids and Lubricants on page 11‑12 for GM approved fluids. • Engine oil and windshield ...