I spend a lot of time looking into this and here is some info for those that need new keys or keys cut for your SUV.
I have successfully cut and programmed 7 keys for my SUV using this info. You can purchase keys from this forum when there is a key sale or you can buy keys from various web sites. I found the cheapest web site to be
www.chipkeys.com
Keys arrive very quickly, usually within a few days. All RX 300s use the SAME keys.
The remote transponder master key is #8501 and it costs $79.
The non-remote transponder key (useful if you add your own new alarm system with remote starter and separate fob) is #ILCO TOY48BT4 and it costs $19.95.
You can program the keys BEFORE cutting them (Just to be sure they will actually work) using the instructions below. Cutting the keys can be done locally but the locksmith must have the proper milling machine. Many do not. These keys are sometimes referred to as laser cut keys or sidewinder keys. Large cities will definitely have locksmiths that can cut these keys. Expect to pay $35. Find another locksmith if they charge more. Some locksmiths may be able to cut the key via the VIN number. Web sites can cut the keys for you such as
http://www.lvsales.com/lvsqcode.htm and there are many others. Search on "laser cut keys locksmith services".
Lexus 1999-2003 RX 300 Key Programming - For NEW UNCUT KEYS
Process works with all keys - remotes, valet, non-remotes
1. Enter the car with a working pre-programmed key and close all doors. Simultaneously depress and release both the brake and the accelerator pedals.
2. Within 5 seconds, insert the working pre-programmed key into the ignition. DO NOT TURN THE KEY.
3. Within 15 seconds of inserting the ignition key, depress and release the accelerator pedal 5 times.
4. Within 20 seconds, depress and release the brake pedal 6 times.
5 Within 10 seconds, remove the working pre-programed key from the ignition.
6. Within 10 seconds, completely cover the remote head off the pre-programmed key with aluminum foil, hold the head of the new unprogrammed and uncut key next to the pre-progammed key head and insert the pre-programmed key back into the ignition.
7. Depress and release the accelerator pedal one time. The security light should now begin flashing to indicate that the computer is reading the new key and programming the system.
8. Leave the pre-programmed key in the ignition for at least 60 seconds with the new unprogrammed key head still next to this covered pre-programmed key head. When the security light stops flashing, the programming process should be complete.
9. Test the new, uncut key. Place the pre-programmed key (still covered with the aluminum foil) into the ignition and verify that the SUV will not start since the transponder signal cannot be read. Remove the key and place the newly programmed uncut key next to the covered pre-programmed key head and insert the cut key into the ignition again. Turn the key and see if the SUV starts. If it does the new uncut key has been successfully programmed into the vehicle's electronics.
10. If this is a new remote master key, test the remote functions on the new key head also.
Lexus 1999-2003 RX 300 Key Programming - For NEW CUT KEYS
Process works with all keys - remotes, valet, non-remotes
1. Enter the car with a working pre-programmed key and close all doors. Simultaneously depress and release both the brake and the accelerator pedals.
2. Within 5 seconds, insert the working pre-programmed key into the ignition. DO NOT TURN THE KEY.
3. Within 15 seconds of inserting the ignition key, depress and release the accelerator pedal 5 times.
4. Within 20 seconds, depress and release the brake pedal 6 times.
5 Within 10 seconds, remove the working pre-programed key from the ignition.
6. Within 10 seconds, insert the pre-programmed key back into the ignition.
7. Depress and release the accelerator pedal one time. The security light should now begin flashing to indicate that the computer is reading the new key and programming the system.
8. Leave the new key in the ignition for at least 60 seconds. When the security light stops flashing, the programming process should be complete.
9. Test the new key. Place the key into the ignition and verify that the SUV will start.
10. If this is a new remote master key, test the remote functions on the new key.