do other devices pair with the phone other than the car? if not try restarting the phone. my atrix 4g's fingerprint reader sometimes quits, but a restart usually fixes that. for their pairing instructions see here... in case you might have skipped something and didn't realize it.
Hyundai Bluetooth Compatibility
i did notice that is says it doesn't support pairing with a droid x2... but it should still handle the basic calling functions