I can't get messages from my iPhone to my car's audio system - does iPhone support MAP?
Firstly, all iPhones since the iPhone 5s support the Message Access Profile (MAP). For more information see Bluetooth profiles that iOS supports.

As for how you can get this to work, it seems to me you’ve done a great job of trying to troubleshoot this. However, one thing you probably missed (because it isn’t at all obvious!) is the fact you may need to enable Show Notifications.

To do this:


On your iPhone go into Settings
Tap on Bluetooth
Find the listing for your car’s device and tap on the info icon (it’s the blue circle with an i in it)
Now make sure that Show Notifications is enabled


Once you’ve done that, try again to use the messages function. Please note, however, that many car units won’t import messages already on the phone, so the best way to test this is to have someone send you a text while the phone is connected.