I bought an 1999 RX300 from its original owner. it came with 3 keys 2 with buttons (one with a lexus logo and one with nothing) and one key with a lexus logo and no buttons. The only key that works remotely is the 3 button logo key. the second 3 button key has no response. The previous owner tells me that they both have worked in the past. I have tried reprogramming it with no luck but after reading some other threads it seems to me that i may not be using the correct master key. Is the key with no buttons the master? or the logo 3 button? how can i tell??

 

Is one grey and one black? Grey is valet key.
Are batteries good in the key in question? Ultimately, you may simply have bad keyy, happens. Water damage, for example. Pop key open, there is greenish plate inside with contacts that gets oxidized. Take eraser and clean those contacts. Install new battery. Re-programm it. See what happens.
Dealer sometimes does not charge for a trivial thing like key set up.

 

Yes the no button key is grey.
both keys look to be in good working order with the little red light blinking. I've tried reprogramming but no response. I was wondering if the 3 button logo key is the master?

 

There is good explanation in the sticky 'having problems start here mega thread"


One can not make assumption based on color and buttons unless the keys were provided at the first point of sale by Lexus. One can purchase keys and have duplicates made. "master key" is the one that has the magnetic signature stored in the ECU as master. With the master key (sort of like a password for the ecu) you can enable ecu to accept other keys with their unique signature.

If you are in procession of those keys then there should never be a need of reprogramming. You can only make things worse.

What functions are you trying to reprogram? There can be a problem with the receiver [unless at least one key is working fine] or the door lock actuator(s) [unless they can be operated by the switch inside the door].

Salim

 

Yes Salim i am trying to program the second 3 button key. the last owner said it was the one they were using up until the car was sold to me but when i was picking up the car he noticed it no longer opened the doors remotely. he grabbed the second (spare) key(the one with the logo) and that one worked.
I replaced the battery and tried to reprogram it but still nothing. I could be doing it wrong but after reading other threads it seems as though i need to have the master key to do the reprogramming.

 

I believe the master key acts differently in the ignition as it relates to the security light. When you put your keys in the ignition, does the security light go out? I *think* that indicates a master key if it does.

I believe button-less keys can also be masters.

 

Just in case this was never solved, insering a Master Key (3-button remote) into the ignition will turn the security light off immediately. Inserting a non-Master Key (3 button remote) into the ignition will not turn off the security light for 2 seconds. Insering a Valet Key (grey, no remote buttons) into the ignition will not turn off the security light for 2 seconds.