I have an Pioneer AVH-4100NEX, and everything has been working fine last couple of months.

All of a sudden, when I plug in the USB on my phone, the head unit doesn't detect it (it still charges my phone through the head unit so I know the connection is there)

Even if I launch Android Auto manually on my phone (Nexus 6), it loads as if it's not connected to a head unit. Bluetooth audio/phone connection to the head unit still works.

I rebooted the phone but that hasn't helped. Anyone else having similar issues?

Also, is this the best place to post about this? I wasn't able to locate Pioneer user forums other than this one.

Thanks

charging not mean correctly connected . 1st thing you have to try another cable . if not work for you try to use another phone . also check your smartphone settings to be (Android Auto)

If you have any other usb devices plugged in, take those out and then try. 

I would also disable any anti malware/antivirus on your phone, they could be hijacking the connection.

Hey Natv, 

Did you figure out the problem?

I had this same issue, same stereo, same phone. My issue was that the green ground wire came out of the box with a very short exposure cut & appearantly lost contact with the crimped connecter I'd used. When I removed the unit went back to the green wire & used a wire stripper to make a longer exposed cut of the wire, used a new crimped connecter everything has been great again.