There is a diagnostic menu also. I don't think this is in the manual so this is good.This is for the 07+ seadan and the g37. Not sure how to do it with the 1st generation G. I know I can do it on my Foci too and gives me some cool crap like oil temperature reading and water temperature,etc etc
You have to start your engine
turn the audio off
hold down the setting and the same time turn the volume controll either way at least 40 clicks
it will give you a beep when you get there
there is is some adjustment and trouble code reading
navigation menu
you can even test the speakers
climate conroll
etc etc
Can't remember all it has been a long time since I used it. Actually on the 08 never tried it. I did on my 07.