Using the “Delete All Name Tags” Command
This command deletes all stored name tags in the Hands-Free Calling Directory and the OnStar Turn-by-Turn Destinations Directory, if equipped.
To delete all name tags:
1. Press and hold 
for two seconds.
2. Say “Delete all name tags.”
See also:
Vehicle Symbol Chart
Here are some additional symbols that may be found on the vehicle and what they mean. For more information on the symbol, refer to the Index.
Airbag Readiness Light
Air Conditioning
...
Tachometer
The tachometer displays the engine speed in revolutions per minute (rpm). ...
After Off-Road Driving
Remove any brush or debris that has collected on the underbody or chassis, or
under the hood. These accumulations can be a fire hazard. After operation in mud
or sand, have the brake linings clean ...