See also:

Battery Power Protection
The battery saver feature is designed to protect the vehicle's battery. To prevent battery discharge while driving, the following systems are reduced automatically in two stages and then turned off: ...

TTY Users
OnStar has the ability to communicate to the deaf, hard-of-hearing, or speech-impaired customers while in the vehicle. The available dealer-installed TTY system can provide in-vehicle acce ...

Engine Cooling System Messages
A/C OFF DUE TO HIGH ENGINE TEMP This message displays when the engine coolant becomes hotter than the normal operating temperature. To avoid added strain on a hot engine, the air conditioning com ...