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:
Place a Call Using a Stored Number
1. Push . System responds: “OnStar
ready.”
2. Say “Call <name tag>.” System responds: “OK, calling <name tag>.”
Verify Minutes and Expiration
Push and say “minutes” t ...
If Steam is Coming from the Engine Compartment
WARNING
Steam from an overheated engine can burn you badly, even if you just open the
hood. Stay away from the engine if you see or hear steam coming from it. Just turn
it off and get everyone aw ...
Climate Controls
These systems control the heating, cooling, and ventilation. ...