Why does my iPhone not connect automatically to Bluetooth when receiving phone calls?

[iMore Question]

iPhone normally connects automatically to Bluetooth in vehicle when making or recieving phone calls, but now started to initially ring on vehicle speakers like normal but then when call answered the callers voice is only on the phones speaker and transmit mic only picking up on phone not on vehicle. Is there a setting on the phone that's changed? I can't seem to find.

 

[fredriks]

I've seen this on phones that haven't been restarted for a while so true that first. Second thing is to remove your phone from your cars Bluetooth and your car from phone so you can resync them again. Often this solves this kind of problems.