[Cadillac_Driver01]

I am aware that through a bluetooth connection the 2013 ATS is unable to play music. Instead I use a charging cable and plug it into one of the USB outputs inside the center console. Sometimes this allows me to play music through the charging cable, but sometimes it doesn’t allow me to. (I have an iPhone.) Why does this not always work? Is there a way to fix this?

 

[artscadillac]

I only use a USB drive. On the USB drive, CUE needs certain formats, like MP3.
They are listed in the owners manual. If your phone has different formats, that could be the
cause. It also can have problems if too much music is on a USB.

I am only guessing CUE might treat the phone like a USB Drive.

 

[CaptSoloNJ]

My CUE does play music from the Android SmartPhone thru the Bluetooth as though it was a USB Drive (need to cycle thru the choice). Problem is the extremely low volume output. Need to crank up volume setting, which then blasts the sound for phone voice and radio, when the music function is turned off.

For me, It's been best to put the music on the SD Drive or a USB Drive.

 

[Sergio526]

I've definitely played the audio from YouTube videos over bluetooth in my 2013...pretty sure. That might be a permission that needs to be granted when you initially pair?

 

[Mitt]

You should be able to stream using bluetooth. Make sure your software is updated on your phone. I had an issue that mine would periodically stop streaming and once I updated the iOS it worked fine.

 

[TwiceHorn]

When you plug up a phone to a USB port, there are "options" for how the phone appears to the port as a "device." In android, you can change that in developer options. It can appear as simply a USB memory device like a thumb drive, or a media player (MTP) like an ipod, or it can be "charge only" etc. To some extent, this is automatic but it can go wonky and manually changing it can fix it back.

I am sure the iphone is the same way, but I am not sure how you access those settings.

Even if the settings are correct, it can take some time for your head unit to "read" the contents of whatever device you plug up, even if it's just a thumb drive with no directory structure. When you plug up a phone, it has a complex directory structure and it can take some time to scan and read the music files, if that is what you are aiming to play. And sometimes that glitches and doesn't happen or happen in a reasonable time.

So, if it works intermittently, a) give it some time and b) try unplugging and replugging and c) dig around to find the settings for how it appears once plugged into a USB port.

Diggging around, it seems that IOS started locking out USB access automatically if your phone hasn't been unlocked for an hour to avoid USB hacking. How to Access Controls for USB Restricted Mode in iOS 12

That right there might explain it.