Since the update, only some of the bluetooth functions work for me. I have a 2011 Toyota Corolla with Bluetooth built in. On ICS, everything worked fine. Now, the only apps that work through my car stereo are the stock music player, and PowerAmp. No other apps come through any more. Mort Audiobook player, google navigation, motocast, and numerous other apps I have tried no longer work through the car stereo via bluetooth. Furthermore, the voice dial through my car stereo no longer places calls through the phone. I can make, receive, and hang up calls just fine with the controls in the car, but to place a call, I have to pick up the phone and dial.
I have tried unpairing/re-pairing the phone, factory resetting the phone, and even unpairing/factory resetting/re-pairing the phone. All net the same results.