jsmith

I got a replacement 2nd fob for my CPO nx200t. I am told that the missing one that's out there is still "married" to the car and can open and start it, even after they reprogram the new key. They said I needed two NEW fobs to kick that missing one off the system. Isn't that the whole point with reprogramming immobilizers? They are trying to tell me the original fobs were identical so the missing spare can't be kicked off the system. Any help would be appreciated.

Thanks,
Joe

MKenM

They are twins but not identical. Each fob carries with it all the presets, seats mirrors etc. It sounds like they programmed the new fob to its new twin or the car. Not sure which they program.

Unless your old fob has some ID on it that would tell someone where they might find your car the chances are slim that the person who MIGHT have found it would know which Lexus it belonged to. They would have to drive around pushing the key fob at every Lexus they came by.

jsmith

Well it seems that the PO presumably lost it and could possibly still have possession of it. He would also know the car, including its VIN. I know it's a remote chance but I hate knowing that possibility exists - assuming that the dealer service rep knew what they were talking about. A locksmith explained to me that the immobilizer portion is a separate program from the remote functions. There are unique key signatures/characteristics that are used so that the car recognizes it. When they reprogram the immobilizer memory, all the physically present keys get memorized and everything else erased. That's how it was explained to me.

offroad200

There's programming a new key and then there's resetting the whole system. It's called reseeding. In order to kick the old one off, you'll have to reseed the computer. The problem with used keys is they may or may not always be able to be reprogrammed. Even if they are able to technically be reprogrammed, there's still no guarantee the used key will work. Some Lexus models don't allow the reprogramming of the key, some do. I'm not sure which models though. Hence why they might be saying you need 2 new keys. Lets say you only program one, then you lose that, then you're right back where you were.

jsmith

So why would you not "reseed" the computer if you have the two physical keys at hand, wouldn't that kick the missing one off? The explanation about needing two new ones is still bogus in my mind. I called up Lexus USA and they told me the old fob would be useless now.

offroad200

Because reseeding the computer takes a bit longer and will cost you more money than just programming a key. But's it's how they make sure old keys won't work.

jsmith

Not costing me anything under warranty - them, it's their job. I reached this same conclusion but to be sure I called Lexus corporate who reassured me the missing key is now useless. Not wasting any more thought on this, just annoyed at the illogical thinking on service policy if that was indeed the case.