My iPhone no longer auto connects to the BT receiver in my car after the recent iOS update

Hello Ataraxy01,

Thanks for choosing the Apple Support Communities. We understand you want to connect your iPhone to your car using Bluetooth. We have a few steps that will help you resolve this. Give those a try below.

How to connect your iPhone, iPad, or iPod touch to your car - Apple Support

"Connect using Bluetooth

1. Restart your device.
2. Go to Settings > Bluetooth, and turn off Bluetooth. Wait for about 5 seconds, then turn Bluetooth back on.
3. Check the manual that came with your car for more information on how to pair with a Bluetooth device. Most cars require a phone setup on the car display. 
4. If you've connected multiple phones to your car stereo, try renaming your device: Go to Settings > General > About > Name, and type a new name. Then try connecting again.
5. Update your device.
6. Make sure that your stereo is using the latest firmware from the car manufacturer. Check your car's manual for more information.

If you still can't connect, contact Apple Support.

Connect using USB playback

1. Restart your device and your car.
2. Make sure that your device is unlocked and on the Home screen.
3. If possible, try to connect using another cable or USB port. Check the manual that came with your car to learn how to connect an Apple device.
4. Check your charging port for any debris or damage. Make sure that your charging cable is properly inserted into the port.
5. Update your device.
6. Make sure that your stereo is using the latest firmware from the car manufacturer. Check your car's manual for more information.
7. Try playing audio from a different app. If you can't play audio from a third-party app, contact the app developer for help. If you can't play audio from an Apple app, contact Apple Support."

We hope this helps.

Cheers!

Ataraxy01,

If it is an aftermarket unit, our best recommendation would be to reach out to the manufacturer of the receiver. Outside of the steps above, there wouldn't be any other settings in iOS to change to tweak or address this behavior.

It may be that the manufacturer has released an update on their end to restore functionality in the way you'd prefer.

Take care.