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:
Denali details
The iconic Yukon Denali delves deeper into the luxury SUV realm with enhanced
features and craftsmanship that distinguish it from other models. It is a
comprehensive package of performance, amenit ...
Tire Rotation
Tires should be rotated every 12 000 km (7,500 mi). See Maintenance Schedule on page 11‑3.
Tires are rotated to achieve a uniform wear for all tires. The first rotation is the most important.
...
Tire Terminology and Definitions
Air Pressure: The amount of air inside the tire pressing outward on each square inch of the tire. Air pressure is expressed in kPa (kilopascal) or psi (pounds per square inch).
Accessory Weight: The ...