With the NAV screen on, push the top left soft button, which should be the "CD" if your CD is playing. If you turn on the radio (pressing the "band" button", it will be a soft button "FM1" or what ever the last radio band was on when last turned off ........
You have now replaced the NAV screen with the "band" or "CD" function and it won't show again until you press the MAP button.
You have now replaced the NAV screen with the "band" or "CD" function and it won't show again until you press the MAP button.