I am having the same problem.
Started a couple of months ago with one key fob, so I switched to the other one and didn't have any more issues until yesterday.
Now I have intermittent issues with both key fobs. Tried replacing the batteries and it did not help.
My only other thought is that the cars battery may be getting weak. I still have the original battery in the car so it is about 5 years old. Still seems to start the car fine though.
Anyone else have any ideas?
Just found this thread....sounds like an expensive fix: