[smurfysmurf]

Another workaround instaed of having the music app or adding a single song as many people have mentioned is opening whatever app you perfer to play music and hitting the play button prior to plugging it into your car system. Then, as the iPhone is plugged in and your car recognizes it, it will see an audio file on the car - the one that is currently playing. It will continue to play that song.

[mabcat]

While my car is in the shop getting unsmashed I've had the pleasure of four different cars and four different sound systems in as many weeks. That's how I know the workaround won't get it done on a Peugeot 308. "Spotify's playing? Nah, let's hear that song you like whose name starts with '('. Spotify's grabbed the audio output again, almost as if you opened it again and pressed play? I can help... And you wanted it on single-track repeat, right?"

Never thought I'd be happy to see Carplay again with its 3-ring circus of UI tomfoolery, but there it is.