Friend of mine has an older prius 2009 or 10 without navi we've never been able to play music from his iphone through the car via bluetooth.
The phone will play audio through bluetooth for phone calls and google maps. Because google maps has an option that allows you to play audio using the. "Play as Bluetooth phone call" option.
Why doesn't any of the music apps have the functionality? Is the problem the prius? Or the phones? or the applications themselves?