Contributed by: X5world

1. Turn on engine (or key to
   
   position II)
2. Push the MENU button, then select SETTINGS menu.
3. Push and hold the MENU button while in the SETTINGS screen for about 5-10
   
   seconds. The SERVICE MODE menu will appear. Let go the MENU button.
4. Select ONBOARD COMPUTER menu.
5. The SW version will show you what NAV version you have.