Have a 2005 LS430. One of the smart keys works as it should. The other smart key will unlock using the remote and start the car with the key in the ignition, but the key is not recognized by the trunk or the outside door handle lock/unlock. Also if I turn the ignition without the smart key inserted, I get a message saying that the key is not recognized. I replaced the battery, but the same thing. This key has apparently had a lot more wear than the key that works properly. Is there a way to "reset" the key so it works properly?
Thanks.

 

Is the key identicle to the one which works, does it have the same red color on the lock button?

 

Has it ever been reprogrammed, if so it will not work ever

 

Appears that the transmitter RF portion has failed

 

If the RF transmitter is kaput, I assume that's why the car doesn't recognize the key for the ignition or doors/trunk, but will work when the button is pushed to lock/unlock. Seems odd that the ignition recognizes the key when it's inserted (will turn and start the car), but not when it's 6" away. Especially since there's a new battery.
Also the trunk button doesn't work on the key.

 

has that key ever worked?
if not you have a key from another car that has been reprogramed.you cannot reprogram a smart key that has been programed at the factory.it can only be programed for one ecu.you have to buy a new key and have it programed.do not buy a key off of ebay as you will be in the same boat.

 

Are you sure it isn't the valet key? You should have two smart keys and a valet key that looks much like the others that doesn't work on trunk, etc

EDIT - took a picture to illustrate the difference