Tried replacing the remote's battery with no luck. Spare works fine. Bad remote?

I assume you mean the remote to unlock your doors?

Was it working before? When did it stop working?

real easy to reset if the battery in the remote is fine. make sure you ave all remotes there and do all at the same time. turn the key to acc then to off , 3 times in a row. and then push the button in the drivers side door frame 3 times, then push each remote, until they lock or unlock the doors. should work. somebody correct me if im wrong.

Brought it to the dealer, they confirmed it went bad and replaced it. Odd thing is, they also notices that the power lock actuator on the driver's side went bad, where it never had a problem before bringing it there. They ordered a new one under warranty. Go figure.