Entertainment System didn't recognize iPhone..too cold?

This morning my 2016 Prius c 2 would not recognize my iPhone 6 through the USB port, while it connected via Bluetooth. It wouldn't charge the iPhone even though the USB port appeared to have power (plugged a USB port tester into the port). The phone charged through a cig lighter adapter using the same phone cord.

This is the first sub-freezing morning I've had with the Prius (it's a 2016 holdover that I bought in July), but the car had been running for probably 10 minutes or so before I plugged the iPhone in, so the cabin temperature was around 60.

Got to work (a nearly 1 hour drive) and for chuckles I shut the car off then turned the key on again. It connected to the iPhone and started charging normally. I'd usually blame any connection issues on the iPhone, but this seems more like a car issue.

Anyone else have issues with the USB port in cold weather?

 

What I plan on doing the next cold morning (it was 42 degrees this morning, no problems, supposed to be in the teens tomorrow) is to see if things are OK, if not do the following.

Try the wife's iPhone (same model as mine but has not been updated to iOS11 yet and has never been connected to the audio system).
Try my ancient iPod Touch (so old it's stuck at iOS 6)
Try a USB memory stick with mp3 files on it to see if it can be read (never done this before, should try tonight).

What I should do at lunch today is monitor what the charging current to the iPhone is. Keep in mind this has worked pretty much without issues since I got the car in July.....until I got iOS 11.....it took multiple reboots of the phone to get playlists to work on the audio system again - or even the pause/play button.

 

I do have an adapter in the 12volt socket (I think it's Anker) that has 2 ports, 1 Apple, 1 other and that works fine with my phone. I started using Bluetooth but the GPS app (Waze) insisted on treating any audio it produced as a phone call, and I wanted to see album art.

 

Plugged the USB analyzer into the port during lunch. It appears it's capable of around 1A. No problems with either my iPhone or my iPad (which has never been connected before).

 

According to page 306 of my manual, it states that the head unit is compatible with iPhones up to the 5. So that tells me it's capable of charging an iPhone. Even if it wasn't the phone should say "Not Charging". It's possible that it isn't compatible with an iPhone 6, but I would expect it not to work at all.

Anyway.

Nice cold 18 degree morning on Saturday. Plugged the phone in and....no problems. So maybe it's a one time thing.

 

I think I'll just blame the problems on my iPhone and an updating iOS. It was -7F this morning and had no problems connecting to the head unit.