iphone 5 blue tooth problems

Since "upgrading" to iPhone 5 the blue tooth synchronization between my car and the iPhone doesn't work correctly. I'm still able to make outgoing calls with my vehicle bluetooth hands free, but whenever I try to answer an incoming call it seems to connect but the caller can't hear me and I can't hear them. I ultimately need to transfer the call to the handset or turn on my Bose earpiece handsfree device. I've gone back and tested this with my wife's iPhone 4 and her phone still makes and receives calls just fine, so at this point I'm assuming it's an iPhone 5 issue. My dealer is also confirming this is a bug with iPhone 5. Is there a patch?