See also:

Overview
The GMC Sierra All Terrain HD concept is an exploration of heavy-duty truck capability combined with greater off-road versatility. It is highlighted by a bold exterior design, enhanced all-terrain ...

Connections
OnStar Hands-Free Calling allows calls to be made and received from the vehicle. The vehicle can also be controlled from a cell phone through the OnStar mobile app. See www.onstar.com for coverage map ...

Using the “Dial” or “Call” Command
1. Press and hold for two seconds. 2. Say “Dial” or “Call.” 3. Say the entire number without pausing, or say the name tag. Once connected, the person called will be heard through the audio ...