My Driver 1 key fob stopped automatically unlocking the doors on my TL when I walk up to it the other day and I can't figure out why. The Driver 2 key fob works fine.

I can manually push the unlock button and it works. If I unlock the car with the Driver 2 fob and get in the drivers seat with my Driver 1 fob, all my settings and seat positions go into effect so it recognizes the Driver 1 fob just fine. I've gone through every single setting and everything is fine.

Any ideas? The only thing I haven't tried yet is resetting back to factory defaults and then re-doing all my settings.