How do you determine if a key is a "Master"?
 

I bought an RX300 with only one key, an aftermarket. It operates the ignition to start and drive the car, but does not operate the door locks. So I have a vehicle I can't unlock if I use the electric door locks inadvertently when I get out.

From the forum posts, A "master" key can initiate the sequence to reprogram a new chipped key, but the "valet" and/or wallet key cannot. Is this a correct assumption?

Is there a way determine if the aftermarket key I have is in fact a "master" other than trying to program another programmable VIN-cut key?

Is it "normal" for the ignition key to NOT work the door locks? Does this mean that either my door lock tumblers or the ignition switch tumblers have been replaced?

I figure my first option is to to get a good locksmith to make a door key from the VIN. This would allow me the use of the car and determine if the doorlocks and ignition lock are the same pattern. >> https://www.ikeyless.com/ << seems to be a source of keys also.

Option two is the $800 to $2000 for the full-on dealer ECM/key replacement therapy...

It'd be much nicer to only be out maybe $200 and get the show rolling for me. Thanks for any insights -M-

Welcome to ClubLexus. I don't have all your answers, but I have some.

The valet key is not a master key. I don't know about the credit-card-sized key. Have you tried the key on the rear hatch lock? The glove box lock? So, you actually have 5 locks on the RX300 (2 door, 1 hatch, 1 ignition, and 1 glove box).

To get them all common, you have to figure out which keying is the majority, and hopefully that keying agrees with the VIN. You usually hear about locks being replaced rather than rekeyed on cars. I guess you can price both alternatives out. Some of the ClubLexus sponsors are Lexus dealers and sell locks and keys at discount prices and can probably help you.

What you have is not normal. Master keys work all 5 locks. Valet keys do not operate the glove box lock. Since you have a key that works the ECM, I don't think you need to consider the ECM replacment.

A key which operates the ignition (Valet) should manually operate the doors also. Not sure what's going on there!

A valet key will NOT work with the glove box. So if the key that you have locks/unlocks the glove box, it should be a master.

To see if the transponder chip in the key is programmed to the car as a master, watch the small red security light (it flashes slowly with no key inserted.)

Put the key in the ignition and if the light goes out immediately, it is programmed as a master. If it goes on for about 2 seconds and then goes off, it is programmed as a valet.

This only applies to the transponder chip in the key, not if the key is a valet or master cut key (although the only physical difference I have noted between a master and valet key is that the master has a small ridge along both edges of the key and valet does not.)