Q: usb audio not playing through car sync after updating to ios 10.

I have the same issue.

I drove to work on iOS9, audio playing just fine out of my car (Fiat Panda, Blue&Me system, connected via Lightning cable).

Updated at work to iOS10, suddenly the car doesn't pick up any audio output from the phone. The phone still charges, however.

The phone says it's outputting to "Dock Audio", but the car says "No Source Available"...

The only way I can use Bluetooth is to use a dongle and cable to the Aux port, so not really a good long-term solution.

I am having the same problem with my iPhone 6s Plus. I have it plugged into the USB of my kenwood stereo in my car. I can charge it from the stereo and skip songs from the stereo buttons, but sound only comes out of the phone speakers. This is very frustrating because I don't like Bluetooth. Any help would be great.

I have the same issue connecting to my car stereo via USB (not carplay). The Stereo recognizes that a device is plugged into it, but the iPhone doesn't recognize it as an output device and only uses it to charge. (It is not selectable either)

The Stereo is a Kenwood dpx501bt if it matters.

I had a friend plug their iPhone 6s running ios10 into my kenwood USB and the audio worked fine, while my 6s plus doesn't. This is somewhat comforting. I'm going to try a restore and see if that fixes this glitch.

I can also confirm that this issue is present in every USB audio device I've tried (multiple car audio systems).

I experience the same issue with an iPhone 6, iOS 10.0, 10.1, and 10.2

addionally, any USB audio target (like a USB DAC connected via CCK) no longer works.

Count me in. After installing the iOS 10.0.2 update, When plugged into the USB port, my iPhone 6 plays music from the iPhone speakers while the song playing is displayed on the Pioneer radio in my car. I can find no way to route the music back to USB.

When I updated to iOS 10.0, this was not a problem.

Ok. I did a hard reset on the iPhone after 10.0.2 didn't fix the issue. I did not restore any settings or data.

It now worked in the car again.

I did another hard reset and restored everything. It was no longer working in the car.

Therefore my personal solution looks like it's going to be a hard reset and manually reinstalling everything. I'll start with Google Music and pulling my audiobooks out of iTunes, then testing again. As long as that's OK, I can't see that I've got anything else that would interfere with it, so I'll have to reinstall all my other apps.

Irritating, but as long as it works, I can live with it... need to remember to delete all backups once it's done and confirmed working, then take a brand new one.

I'll post an update once it's all finished, in case this helps anyone else.

Update!

I tried again this morning and my iPhone was still not routing music to my radio so I tested my girlfriend's new iPhone 7 running iOS 10.0.2 and it worked properly. After doing that, I plugged in my iPhone 6 and BAM, working normally.

Does this mean the problem in the radio?

No, I think not. I have tried that experiment, and the upgraded iPhone still only plays audio via its own speakers, not the car.

Ok, all done. That was a lot of work and I've lost my SMS messages, as there doesn't seem to be any way to restore them from the backup without restoring everything (which obviously I don't want to do).

I'll give it a couple of days to settle down, then nuke the backups.

On the plus side, hopefully won't have to go through this rigmarole again until iOS11, and I'll probably get a new phone at that point...