Originally Posted by jimsRX300
I can help shed some light, recently been down this road. Lexus got in a bit of trouble in the late 90's over this master key stuff. Lost a bunch of lawsuits I guess.
The FLAT KEY you have. Place the metal key part in the ignition but don't turn it.
Observe the security light blinking.
Put the chip part against the metal key, by the ignition.
If the blinking light GOES OUT IMMEDIATELY, chip is programmed as a master. New keys / FOB can be made from it. If the light turns solid for a second or 2, it's not a master.
Good luck. My 2003 was programmed as a master. I have made new keys from it.
Good news! My wife's 2002 Coach Ed. wallet/card key is a MASTER key! Jim's post above is right on! To further identify a master key, on one side it will have the key code engraved and on the other side it will have instructions on "How to start engine"
In contrast, when using a gray/valet key, the security light goes from blinking to solid light for a second or two, then off.
I was also curious to see what happens if you had a key but no chip or defective/dead battery, when you just insert the flat key and turn the ignition on everything looks normal (dash lights go on) and it even lets you crank the engine but it does not run. Nice to know in case someone runs into a defective chip/dead battery situation.
Salim thanks for your reply too, I missed that last night, and as our moderator may I suggest we post this info where appropriate, or an actual warning/notice to people who only have one master key to get a second one made because as far as I know its very very expensive to do this without a master key.
I'm assuming anything older than 00 only have flat keys so they do not actually have a chipped wallet/card keys that the 02 and 03 have. We don't have info on 01's.