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:

    How to Check Lubricant
    2500HD with 6.0 L All Other Series and Engines To get an accurate reading, the vehicle should be on a level surface. • For all 4.3 L, 4.8 L and 5.3 L 1500 Series applications, the proper leve ...

    If the Vehicle Is Stuck
    Slowly and cautiously spin the wheels to free the vehicle when stuck in sand, mud, ice, or snow. If stuck too severely for the traction system to free the vehicle, turn the traction system off an ...

    Rear Climate Control System (Rear Climate Control Only)
    A. Fan Control B. Temperature Control C. Air Delivery Mode Control For vehicles with the rear climate control system, the controls are located on the rear of the center console. The system can al ...