Hey guys,

I don't normally post on forums but this issue wasted many hours of my time and I was unable to find a solution anywhere online, so I thought I'd share mine.

My issue was that my wife's phone, a OnePlus 7T, stopped working on our 2019 Mazda CX-5, after her phone randomly did a factory reset on its own (I have no idea why or how still). I tried everything I could, including changing the USB mode, trying different cables, turning on USB debugging, uninstalling and reinstalling AA updates, resetting the infotainment system to factory settings, performing an additional factory reset on the phone, and finally flashing the global ROM (we we on a T-Mobile from B&H Photo Video). Nothing seemed to do the trick. Her phone would work with AA on my 2021 Mazda 3, and my OnePlus 6 would work on both our cars.

Today I was fiddling with my OnePlus 6 connected to her CX-5 and noticed in Settings -> Devices, there was a check mark beside Android Auto. I unchecked it out of curiousity, and my phone disconnected. It wouldn't launch AA anymore. Also because of this I couldn't re-check that option in the settings (not a great design?). I figured somehow this checkmark got unchecked for the OnePlus 7T.

So I changed the bluetooth name of her phone from "OnePlus 7T" to something else, and also reset the infotainment system to factory defaults for good measure. On her phone I deleted the bluetooth device "Mazda" and then when I plugged her phone in, I got the AA launch message to pair and everything started to work like normal!

Hopefully this helps others who are experiencing the same issue.

 

The advice we give any customer with phone connection issues is to delete all the pairings on the Phone and all the pairings on the head unit/Audio.
Start from scratch.

 

This might have fixed it, but I'm almost certain I had tried unpairing her phone on the infotainment and unpairing the Mazda on her phone as well. I didn't think to delete all the pairings on both devices though. Thanks for this advice and I'll try this first if I have issues again.

Do you know if there's a way to re-enable Android Auto for individual devices after it's been disabled?

 

The only issue I had was at first when I tried using a cable that was micro-USB with a USB-C adapter. When I switched to an actual USB-C cable, everything worked perfectly snaptube vidmate . Pixel 3A, 2019 GT PP.