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 mute, press , and then say “Un-mute call.”
See also:
OnStar Additional Information
Transferring Service
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Driving in Mud, Sand, Snow, or Ice
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Traction changes when driving on sand. On loose sand, such as on beaches ...
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 ...