So, for a trivial cost you can get your verbose option. Most people are not going to have any knowledge or desire to have this information, so it's a silly feature to include.
You will need an Android phone already, but these days that is pretty common (particularly for technical people). Just get the error code and Google it, it becomes pretty obvious what it is.
I know my 2007 Lexus has those programmable options like beep durations and such, but I have only found two solutions - paying the dealership $60 to change them, or buying a $15 android app that changes them. I could do it myself, but the codes (Lexus Personalized Settings) are secret. Did you find a free alternative to modify your Prius settings?
http://priuschat.com/threads/geniii-prius-custom-pids-for-to...
But the short is someone else has done the hard work so you don't have to.