2000 Lexus RX 300 wrong key locked up theft system

I am not to good with the alarms for those cars, but you can try disconnecting the positive side of the battery. without the positive side of the battery hooked up use a jumper wire touch the positve cable that you took off to the ground. after a minutes disconnect the jumper wire. hook the battery back up, wait a minute then try her key, you might have to put it in and out a couple of times. There are other moderators tha know more about it but it is something you can try.
ps. make sure the battery has a good charge.

the alarm will not keep the key from physically turning. chances are you might of damaged the ignition lock cylinder.

I looked up service bultein and did not find any in reference to resetting the ignition. I did find that the key has a computer chip in it that locks the ignition system of the vehicle. try using the key with out any other keys around.

How did you solve your problem? I just did the same thing. I mistakenly put the key to my 2002 ES into my wife's 2004 RX and ended up locking the theft system. Please let me know how you solved the problem.

Hello
My garage(not a lexus dealer) told me to use wd40. I used the red spray nozzle and sprayed some in the ignition, put my wife's key in and it turned instantly.
Try it and good luck.

You were lucky, I was talking to a locksmith that deals with just automobiles the other day. Inside the ignition switch there is a split chip. When someone uses a diferent key it breaks off a little piece inside the ignition making it so the igniton is inoperative. The piece is no bigger than a tip of a toothpick. you are lucky that the chip did not break off completly .