Like already stated you need a data connection for the maps.
You can use tile catching.
With a WiFi connections set your destination and let MAPS calculate your route,
it will download all the map tiles necessary. Off you go and it will navigate you to your destination
even after you have lost your WiFi connection.
Only drawback is you cannot change destination unless the new destination is within those map tiles
it downloaded.
Also that is why I have CoPilot, it let me download and keep maps on the TF itself foe occasion
when I can't get data connections (usually I'm tether to my N1 if necessary)