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 
to try the call again or try again after driving a few miles into another cellular area.
See also:
Introduction
The names, logos, emblems, slogans, vehicle model names, and vehicle body designs appearing in this manual including, but not limited to, GM, the GM logo, GMC, the GMC Truck Emblem, ACADIA, and DE ...
Control of a Vehicle
Braking, steering, and accelerating are important factors in helping to control a vehicle while driving. ...
Dual Tone Multi-Frequency (DTMF) Tones
The Bluetooth system can send numbers and the numbers stored as name tags during a call. You can use this feature when calling a menu-driven phone system.
Account numbers can also be stored for use.
...