Last night when I got in my 2000 rx300, put the key in, turned the key, the plastic fob broke and the key wouldnt turn.. Ok, no biggie, have had this happen before. Grabbed pliers, turned key, started, drove home... (fob was in my pocket all the way home)

Printed a new case (yay 3d printers) Figured I really didnt care about the fob, put just the key in new case. (fob still in case, basically right next to key) Went out this AM, put in key, turned, cranked, but no start..

The security light wanted to keep flashing.. I thought the rfid was in the key? Just for the heck of it, I put the key in, put the fob next to it, security light stopped flashing.

Still wont start though.. Does turn over.. So.... By me not having fob and trying to start, did that activate something? Or should it not matter? If I have fob by itself close to ignition switch, doesnt do anything.. If I have key by itself in ignition light seems to want to keep flashing. Once I bring fob close, light goes out..

Can someone explain exactly what is part of security for this? Right now, I've got battery unhooked and resetting that way just for heck of it, not expecting it to really do anything.

Any insight or clues?

Thanks

 

I'm not sure I understand -- did you move the electronic module (buttons and light) from the previous (broken) fob to the new one? That would be needed for the key to start the car, as I understand it.

 

This started to interest me too. I ordered two "Flip Key Case Shell Replacement Lexus RX300 2 Button Remotes" from e-bay, because my keys plastic parts are very worn, one is more epoxy glue than original plastic. I believed that after I get blade copied change was just put in the electronics and battery, no chips sealed in the case, but now I am getting worried. The seller says:"all you need to do is remove the internal component from your old remote and put it in this case." That indicates that Your system should work when both the blade and old case are close to the ignition switch. I will take glue of from my second key later today and try my theory in practice later today (Timezone GMT+2, Athens,Helsinki).

Edit: You might have immobiliser on, here is a link how to disarm it : https://www.clublexus.com/forums/rx-...-bad-keys.html

Timppa

 

The transponder which communicates with the car to allow it to start, is inside the plastic bit with the 2 remote buttons.
So when you take the complete innards and transplant it to your new key you should be fine (as the ebay seller indicates)
I know this because I just had a new key made and they had to replace the transponder to make it work.

Cheers,
Johan

 

 

If you have time please read up the 'having problems start here' sticky thread. If anything in there leaves you confused, please let me know and we will keep improving it.

With key duplication there is a concept of Master_key, slug (ferrite material) that sends out the signature, ECM that has copy of the signature in its memory. The signature of the master key gives permission to the ECU to accept another signature to start. The Key blade is dumb and the slots and ridges allow the cylinder to turn (physically turn only).

Salim

 

Yes; the electronics don't care what key they're inserted into, and transferring the electronic guts to a correctly cut key will allow it to work just fine without any need to reprogram. Using the guts for another vehicle would require reprogramming.