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:
How the System Works
URPA comes on automatically when the shift lever is moved into R (Reverse). A single tone sounds to indicate the system is working.
URPA operates only at speeds less than 8 km/h (5 mph).
An obstacle ...
Starting the Engine
Move the shift lever to P (Park) or N (Neutral). The engine will not start in
any other position. To restart the vehicle when it is already moving, use N (Neutral)
only.
Notice: Do not try to shi ...
Extending Engine Run Time
For a 10-minute extension, repeat Steps 1 and 2 while the engine is still running.
The remote start can be extended once.
When the remote start is extended, the second 10 minutes will start immedia ...