Google Maps not playing as phone call IOS 14

Ever since the option became available, I have played Google Maps navigation directions as a bluetooth phone call over my car radio. My car is a 2009 model and has its original bluetooth equipment. For the last few months, navigation no longer plays as a phone call, though I can still make and receive phone calls. Google Maps is properly set up for playing as a phone call, and I have rebooted the device twice. Volume is turned up. Suggestions?