Voice Command will only function when full coverage of a device's preloaded map is installed. See the owner's manual of your device for instructions to view the myMaps screen and check the installed map coverage.
Voice Command Will Not Work in the Following Situations:
A smaller region of the preloaded map was loaded to the device during a previous map update:
To get full coverage back, update the maps with a memory card installed in the device.
Mapping files may be missing or have become corrupted. If full coverage of mapping is already installed, reinstall the maps with Garmin Express™ software.
For instructions see Reinstall Maps on an Automotive Device.
Voice Command is used in a region which was not preloaded on the device.
For example, a North American device is preloaded with the map of North America. Europe maps can be added and used with this device, but Voice Command will only function with the North America map.