One of my keys lost it's ability to remotely lock & unlock the car.

Service Rep at the dealer told me how to reset the keys - worked great!

1) Insert key into ignition
2) Rotate key to position 1
3) remove key
4) Hold key near rearview mirror
5) press and hold unlock
6) while holding unlock, press lock 3 times
7) release

You will know you are successful if the locks lock on the last push of the lock button on your key

repeat steps 4 - 7 with your other key (otherwise it will loose it's association)

He wasn't sure if it was position 1 or 2 on the car.

I had to try it a couple of times for it to work. I think I had to do the key that was still functional first and then the key that was no longer working.

Good luck!