Unfortunately, you cannot do this by yourself. You must go to a Lexus dealer because these keys are laser precision cut. They only need to know your VIN and they will order the key to be cut from LEXUS. It may take about a week to get your key from LEXUS HQ.
The key has a button which controls the locks on the doors, press once for drivers door and other doors, if key does not work check battery in key.
hit the lock button twice
I had to go to a Lexus dealer for mine. The keys are lazer cut. Cost me 60.00
Car alarm in Lexus ES300 started going off at random when car was parked, not running. I changed the key fob battery (flat watch battery) with a new battery and it fixed the problem.
If you press the unlock button two times it should unlock all the doors.
This link will show you how: http://www.youtube.com/watch?v=Za7pCdUde3U
The amount that a Lexus dealership charges to make an additional key for a Lexus car depends on the year and model of the car.
The amount that Lexus charges to make a new Lexus car key varies by year and model of the car and by dealership.
Lexus has to hook their computer to it to program the key to both lock/unlock and to start the vehicle.
There should be a little Phillips screw on one side of the plastic of the key toward the bottom. Just unscrew it and pry it off with your nail and replace the battery with what is in there, it is probably a cr 2032.
Open the key case with a jeweler's Philips screwdriver. Remove the back cover. Use the Philips driver to remove the two screws that you now see. Remove the battery cover. My key uses a button battery: CR 1616. Note tyhe battery you need and buy a new one (RS store is a good place). Use a jeweler's flat blade to lift the battery up and slide out. Replace with a new battery and reassemble.
The factory remote key cost approximately $450.00 installed as ther is a small computer chip that come with it and has to be installed in the car www.lextechautomotivellc.com