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:
Driving in Mud, Sand, Snow, or Ice
Use a low gear when driving in mud – the deeper the mud, the lower the gear. Keep the vehicle moving to avoid getting stuck.
Traction changes when driving on sand. On loose sand, such as on beaches ...
Erasing Universal Home Remote Buttons
The programmed buttons should be erased when the vehicle is sold or the lease ends.
To erase either Rolling Code or Fixed Code settings on the Universal Home Remote device:
1. Press and hold the two ...
Retrieve My Number
1. Push X. System responds: “OnStar ready.”
2. Say “My Number.” System responds: “Your OnStar Hands-Free Calling number is.” ...