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:
Underbody Maintenance
Use plain water to flush dirt and debris from the vehicle's underbody.
Your dealer or an underbody car washing system can do this. If not removed, rust and corrosion can develop. ...
Manual Transfer Case
The transfer case shift lever is on the floor to the right of the driver.
Use this lever to shift into and out of Four-Wheel Drive.
A Four-Wheel Drive indicator light comes on when you shift int ...
Transmission Temperature
Press the trip/fuel button until TRANS TEMP displays. This display shows the temperature of the automatic transmission fluid in either degrees Celsius (°C) or degrees Fahrenheit (°F). ...