I thought it was the battery (in the smart access remote) so I replaced that. It unlocks the doors but I get the "key not detected" when trying to start car.
I don't recall having tried this key before and don't even know if it worked when I bought the car 3 years ago. it is strange to me that it unlocks doors but that is all. That key also will not let me insert the small end into the ignition.
Both other keys work fine.
Any suggestions?

 

sounds like the inners were inserted in a different housing.the guts of your key is in a different smart key housing. does your key fit the doors? if not that is what happened and you cannot program it.

 

I considered that but the valet remote unlocks the doors. I checked the mechanical key (in the valet remote) and it locks and unlocks the doors. I checked the voltage on the replaced remote battery and it was only slightly low.