HTC myTouch 4G Slide User Manual page 124

124 Maps and location
Genius Button Open Genius Button and use voice commands to make a call, send a
text or email message, search the Web, and more.
Exit Close the Car Dock app.
If you've navigated away from the Car Dock main screen, you can close the Car
Dock app from the Notifications panel. Press and hold the status bar, slide your
finger down to open the Notifications panel, and then tap Car mode enabled.