I as well have a 2002 BMW 745i and am having the same issue. I took the MODE BUS out for a few min and plugged back in to see if it might reset the radio or navagation, nothing. I also went to BMW and asked if I should replace the MODE BUS. One of the techs I spoke with said he didn't recommend that because he didn't think that would be the cause. So I was wondering if there might be something else I can try?
*Car Problems* One night I went to start my car and the front nav screen flickered a bit. As it turned on it looked as if there was no problems. I go to accept the agreement and realize that after doing so both CD options (CD Changer/Single CD) are grayed out as well as the Radio. I scroll down to click, nothing, no sound of any sort (execpt a little crackle out of the front speakers, that happened every now and then previously). I scroll to the navigation, again nothing, just a blank screen where the nav would normally appear. Come to find out most all of the control functions dont work, with exception of the climate control. You can navigate through the menu just fine but when it comes to working nothing happens.
I've tried reseting the MOST BUS by pulling it out and plugging back in. I've tried cutting power to the entire and let it drain a bit (unpluged the battery). Not really to sure what to do from here. Any suggestions? Thank you!!