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 ...

    Manual Operation
    The air delivery mode or fan speed can be manually adjusted. (Fan Control): Press to increase or decrease the fan speed. Pressing or while in automatic control places the fan speed under manual ...

    Reclining Seatbacks
    WARNING Sitting in a reclined position when the vehicle is in motion can be dangerous. Even when buckled up, the safety belts cannot do their job when reclined like this. The shoulder belt cannot ...