Issue with incoming calls on iPhone not routed to car’s audio system

For the past couple of years, I’ve had a problem with my Tesla Model Y not routing incoming iPhone calls through Bluetooth to the car’s audio system. Instead, audio from incoming calls would be routed to my phone’s speaker. Also, if I were listening to a podcast using my phone over the car’s audio system, the podcast would not resume playing after the call was completed. This feature used to work for me and it works for other Tesla drivers with iPhones. It was an annoyance for quite a while. 

I searched on Google and the Apple forums for a solution but couldn’t find one that solved my problem. After finally discussing this with my wife, she hunted around and found an obscure iPhone setting in Settings > Accessibility > Touch > Call Audio Routing. My phone was set to Speaker and hers (which works properly) was set to Automatic. I don’t know how my phone's setting was changed to Speaker but when I changed it to Automatic, the problem was resolved. Incoming calls are now routed to my car's speaker system and my podcasts resume after the call is done. My wife documented this with a bit more detail at https://www.podfeet.com/blog/2023/09/iphone-speaker-call-audio-routing/