See also:

Muting a Call
During a call, all sounds from inside the vehicle can be muted so that the person on the other end of the call cannot hear them. To mute a call, press and then say “Mute Call.” To cancel m ...

Overheated Engine Protection Operating Mode
If an overheated engine condition exists and the ENGINE POWER IS REDUCED message is displayed, an overheat protection mode which alternates firing groups of cylinders helps prevent engine damage. ...

Add-on Electrical Equipment
The OnStar system is integrated into the electrical architecture of the vehicle. Do not add any electrical equipment. See Add-On Electrical Equipment. Added electrical equipment may interfer ...