Slightly Different Key Question

[The Flying Ox]

I bought a 2000 IS200 SE this weekend just gone, which only came with one key. Going by the info on here, it's definitely a master key (black, 3-button, manually opens boot & glove box, security light goes off instantly when put into the ignition). The remote central locking doesn't work though.

I'm 99% sure it's just the fob Battery, but I'm paranoid that if I go ahead and change it I'll reset everything and not be able start the car. I have a new Lexus key ready to be cut and programmed, but I'd like to get the one I have sorted first if possible.

I've looked through all the various "Door Dance" stuff, but they appear to need a working master key in the first place for anything to work. As I say, my key works as far as immobilisation and manual unlocking, but not remote unlocking, so none of my efforts have worked.

Anyone else had a master key that doesn't remote unlock and sorted it out without resorting to Lexus/auto locksmith?

[ChrisIS200SportTTE]

Yes me, exactly the same.

I don't think it's the Battery. Sounds like you need to code the key back to the car using the 'door dance'

If it were me if put a new Battery in the fob (this won't do any harm, or change anything honestly) and then if that doesn't work I'd do the door dance

Your key is a working master key, contrary to the fact it doesn't work to open the doors. :)

[The Flying Ox]

Problem solved. It was the fob Battery being too weak. Was getting an LED flash, just nothing happening.

Off to get the spare key cut and then a fun morning doing the pedal & door dances.