One of the keys to my blue roadster quit working for lock/unlock a while back. Checked batteries, they were good, played with the battery + contacts a little, they looked good, the red light flashed so I tried the resync procedure. Put key in switch, pressed button twice and turned to run position, tried three times with no luck. Decide to try one more time and I accidentally turned the key to start, the car started and then the locking function worked. Just thought I would pass that along, maybe it will help someone.
Just for shikles and grins, try the other key. Sometimes thinks look like they work until the next time you use the other key. Good luck!
.