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Unable to Connect to OnStar Message
If there is limited cellular coverage or the cellular network has reached maximum capacity, this message may come on. Push Q to try the call again or try again after driving a few miles into anoth ...

Charging System Light
The charging system light comes on briefly when the ignition is turned on, but the engine is not running, as a check to show the light is working. The light turns off when the engine is started. ...

Vehicle Overview
GM says the Sierra 1500 Hybrid's gasoline V-8 and electric motors team up for an overall mileage improvement compared with the regular Sierra. The Sierra Hybrid is only available as a rear- or fou ...