On my wife's iPhone 5, after upgrading it to iOS 8, and on my new iPhone 6, iOS 8 has caused all message functionality to disappear. Even the screen to setup the message function on the 2014 Lexus GS is gone. Note: it's an iOS 8 issue and not a iPhone 6 issue.

 

Same problem here too. Got the problem in my GS, my RX and my Tundra. Frustrating and disappointing but I'm sure (I hope), it will be fixed on the next update to IOS 8.

 

Mine works as well as ever after the iOS 8 upgrade.

 

Let me make sure I understand. Your iPhone with iOS 8 displays messages on the console?

 

Yes, it does.

 

Found the problem. Evidently, when the software upgraded, by default it turns off notifications. Turned them back on in bluetooth>settings>notifications. Problem solved.