@PriusTeam : I have an iPhone 6 and a 2016 Prius 2 ECO. The problem is that the Prius insists on sneaking into my iPhone and playing the music stored on it. This does not seem to be happening via Apple's "Music" app because when I check the phone Apple Music is NOT loaded and active on the phone. I tried unpairing both devices from each other and repairing with the car's Bluetooth set to "phone only". That worked until I turned the car off. When I started it up an hour later, the first song of the playlist began playing again, and the car's Bluetooth had switched back to connecting both phone and audio. Setting it to "phone only" isn't really a solution anyway, because I want to use the phone to stream online radio stations using Safari and have them play over the car's audio system. And use Apple's "Maps" app, which is adequate for my purposes. I thought about deleting music from the phone because the music stored on my phone is mainly for workouts. I originally shared it from my computer because I thought I would use my phone at the gym during weight sessions, but it's much more convenient to use a tiny iPod Shuffle and download playlists to it from my MacBook. I read the Prius manual but didn't find anything that would help. Thoughts? It seems backwards to have to shut the music OFF every time you start up the car! And you should be able to stream or play music from the phone over the car's audio system whenever you want to, without having to change a lot of settings to do it.
Shutting it off is exactly what you will have to do. Alternate workaround - keep it on FM until you really want to stream something.
My 12 Prius has had the same issue with every one of my android phones since I bought the car. I tell it to only connect for phone but next time the car turns on, its back to phone and media. It doesn't always connect, most often right when I start the car but sometimes it will connect 10-15 minutes into a drive. It's beyond annoying.
Ours does the same thing. I ended up deleting all music from the phone. Since I did that, it only connects to the phone now.
It's a matter of perspective. This isn't a bug, it's a feature. I like that when I get in my car, if I was listening to Pandora at work, and I select Bluetooth as the audio source, it starts playing what I was last listening to. The audio system should be set on the last thing you were listening to in the car. If you were listening to FM radio, it will start up in FM radio. If you were streaming Bluetooth audio, then it starts with that. If you were listening to a media player attached to the USB, then it will play that on start up. So, if you don't want to listen to your phone, then switch it to something else. This has not been a problem for me so far. Are you saying you were not listening to your music on your phone when you turned the car off, but were listening to something else, and turned the car off, and then it goes back to the phone? If you select the phone as source, it should play what ever you were listening to on the phone last.
I wanted to add something I noticed. For some reason my phone has a few times been defaulting back to what I was playing on Apple Music. I'm not sure why. I have played Pandora since so I'm mystified. Maybe this is the issue being described?