I was looking into upgrading my radio in my 2001 Odyssey (w/Nav). A quick look at crutchfield's compatibility info said "installing new radio will disable Navigation system."
I assume that since the Navigation system uses the radio/amplifier's speakers, and cuts out the radio when "giving directions" that there must be some proprietary connectors between the radio and Nav system. Am I stuck with the factory radio? or does someone know how to make this work?

 

Speaking from one that does not own an Odyssey and guessing at how Honda and most other car manufacture do business, the stock radio has or contains most of the required hardware/software for the navigation system. So yes, if you upgrade your stock radio, navi would be lost. If you have one of those DVD navi system, only the stock radio would work with Honda's navi system because more than likely, the new radio wouldn't be compatible with it even if you were able to hook them together.

 

i havent seen any aftermarket radios that can connect to stock navis.

you'll lose the voice feature on it/.