Emergency
With Automatic Crash Response, the built-in system can automatically connect to help in a crash even if you cannot ask for it.
Push 
to connect to an Emergency Advisor. GPS technology is used to identify the vehicle location and can provide critical information to emergency personnel. The Advisor is also trained to offer critical assistance in emergency situations.
See also:
New for 2010
GM has dropped the long-running 6.0-liter V-8 engine from the Sierra lineup,
leaving the powerful 6.2-liter V-8 for heavy towing needs. The rest of the
Sierra's eight-cylinder lineup benefits from ...
Listing All Paired and Connected Phones
The system can list all cell phones paired to it. If a paired cell phone is also connected to the vehicle, the system responds with “is connected” after that phone name.
1. Press and hold for tw ...
XM Radio Messages
XL (Explicit Language Channels): These channels, or any others, can be blocked at a customer's request, by calling 1-800-929-2100 in the U.S. and 1-877-438-9677 in Canada.
XM Updating: The encryption ...