I simply yanked the Data Communications Module (DCM) fuse on my GR Corolla, but that has the unfortunate side-effect of also disabling the microphone. That means the only way for me to take hands-free phone calls is with the speaker phone option, so I've simply stopped taking phone calls at all when I'm driving.

When researching how I might be able to do something more surgical I ran across this post by someone who did it with their Tacoma:

https://www.tacomaworld.com/threads/simpler-solution-for-dis...

Reading this HN post on the Chevy Volt it's starting to look to me like the general approach of installing a 50ohm "silencing antenna" could end up working for a lot of different cars out there. I'll certainly be giving it a try on my GR Corolla now so I can get the microphone back while still keeping the DCM disabled.