"OEM 4.3" HD Radio Hidden Menus
Radio off, ignition key to accessory, or on (radio shows "Audio Off")
Hold down "6" key
Spin the tune knob to the right at least 30 clicks
Note that on the 4.3" unit, there are more menus "behind" the first one; in other words, repeating the same sequence after you are in the version number menu takes you to factory test menu 2 (Loudness ON-OFF), and then repeating it again takes you to factory test menu 3 (Eq ON-OFF)"