See also:

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 ...

End a Call
Push . System responds: “Call ended.” ...

Infotainment System Overview
The infotainment system is controlled by using the buttons on the faceplate and the touch screen. See “Infotainment Control Buttons” in this section for more information. ...