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
    To get an accurate reading, the vehicle should be on a level surface. If the level is below the bottom of the fill plug hole, located on the transfer case, the vehicle will need some lubricant ad ...

    Under the Hood
    195-horsepower, 4.3-liter V-6 with iron block and cylinder heads, cam-in-block, two valves per cylinder and 260 pounds-feet of torque 302-hp, 4.8-liter V-8 with iron block and aluminum cylinder hea ...

    Roof Rack System
    The roof rack cross rails can be locked in four positions along the roof rack side rails. Lift the lever to release and move the cross rail. Push the lever down to completely engage into the side ...