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:
Wheels and Trim—Aluminum or Chrome
Use a soft, clean cloth with mild soap and water to clean the wheels. After rinsing
thoroughly with clean water, dry with a soft, clean towel. A wax may then be applied.
Keep the wheels clean using ...
Noise Control System
The following information relates to compliance with federal noise emission standards for vehicles with a Gross Vehicle Weight Rating (GVWR) of more than 4 536 kg (10,000 lbs). The noise control syste ...
Transfer Case
Refer to the Maintenance Schedule to determine how often to check the lubricant
and when to change it. See Maintenance Schedule on page 11‑3. ...