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:

    Leaving the Vehicle with the Engine Running
    WARNING It can be dangerous to leave the vehicle with the engine running. The vehicle could move suddenly if the shift lever is not fully in P (Park) with the parking brake firmly set. And, if you l ...

    Pulling a Trailer
    Here are some important points: ○ There are many laws, including speed limit restrictions that apply to trailering. Check for legal requirements with state or provincial police. ○ Do n ...

    Exterior
    Painted black and trimmed in chrome, my Yukon Denali test vehicle looked more like its Escalade corporate cousin than a tough truck. The Yukon is probably the safest-looking of the three siblings, ...