Hello,

I have an '07 ES350. I was riding my motorcycle today and the key to my Lexus fell out of my pocket at 140mph. I recovered it to find that it popped semi-open. The key battery had become loose and damaged. The microchip looks just fine, as well as the key fob itself. I replaced the key battery and the key was not detected by the car. I used the procedure to start the car by holding the fob up close to the start button. It worked just fine, but the key fob will no longer lock and unlock the car. Is there some kind of initializing procedure to restore this functionality? The key battery was out of the fob for about 8 hours.

 

I've had the batteries out of mine for hours before. Once I put new batteries back in there we're no problems. Sounds like your fob is broken.

 

Does your fob have protective cover on it?
If so, take it off.

There is a faint red light that blinks on the front of the fob when it transmits (you push a button to unlock the car for example)

See if that is happening to show if it is still able to transmit.

If it's not, then I would agree the FOB is damaged.