3 Button Key

[chi]

Hello,

I have 2 x 3 button keys.

One of them has the module, casing is damaged and Battery is flat - Can i change the Battery and get a new casing and have the new key cut without having to reprogram anything?

The other one is super glued together and is working fine but i feel its just a matter of time until the key breaks in the ignition - so again i would like to buy a new casing and swop Battery and have the new key cut.

My only concern is will i need to reprogram the module if a Battery change in the key is carried out.

Thank you in advance.

P.s im flying to HK tmw and i might even look at options to having it sorted when im out there, just a thought.

[sparkystav]

You can just change the casing and get it cut no problem (though finding a place to cut it can sometimes be a problem)

but you may need to reprogram if the key has been flat for a while. though theres a thread on the site that tells you how to do it so you dont have to pay a dealer.

[chi]

You can just change the casing and get it cut no problem (though finding a place to cut it can sometimes be a problem)

but you may need to reprogram if the key has been flat for a while. though theres a thread on the site that tells you how to do it so you dont have to pay a dealer.

Hey Sparky,

TY for the prompt reply, i aim to get the busted and broken key sorted and working 100% before i start messing with my only working key.

The spare set im guessing has been out of action for a long time -.-

I found the thread about reprogramming a new key etc and already have it printed and filed safely :P

[chi]

What does a master key look like?

I only have 2 x 3 button lexus keys -.- both are black

[sparkystav]

They dont look any different,

i think you try them in the car and if its the master the light stays on longer i think

[chi]

They dont look any different,

i think you try them in the car and if its the master the light stays on longer i think

after exhausting the replies on the how to program new keys thread.

I can confidently say that a 3 button key is master key and 2 button key is valet key.

:) im happy as my mate said a master key should be RED ^_^

[sparkystav]

But you said you had two three button keys?

you can only have one master.

and red keys are fords arent they?

[chi]

-.- so i guess it wont be possible for me to find out if the current working key is the master key then?

I have 2 x 3 button keys.

Btw my mate does drive a ford btw

[sparkystav]

There is a way to find out, its to do with how the security light on the dash lights when you p[ut the key in.

cant remember what your looking for though sorry

[dave1]

I have 2 x 3 button keys and 1 x 2 button keys.

The 2 button key is the "valet" key which won't open the boot or glovebox or the lock for the boot remote release.

The 3 button keys will both work everything and are identical so both are technically "master" keys. You should also have a small metal tag which has the key number on it.

Lexus master keys are not red.

[Steviewevie]

The best way to tell is to insert the key into the ignition and watch the blinking Security light on the dashboard. With a master key, the Security light will immediately go off. With a sub (valet) key, the light will stay on for a second and then go off.

The number of buttons on the key isn't an infallible guide. Yes, when the car was brand new the 3-button keys will have been masters and the 2-button keys will have been subs. But unless you've owned the car from new you don't know if someone might have re-programmed the keys at some point (e.g. the 3-button key could have been turned into a sub and vice versa).

[dave1]

The number of buttons on the key isn't an infallible guide. Yes, when the car was brand new the 3-button keys will have been masters and the 2-button keys will have been subs. But unless you've owned the car from new you don't know if someone might have re-programmed the keys at some point (e.g. the 3-button key could have been turned into a sub and vice versa).

If a 3 button key had been reprogrammed to be a sub key then I would imagine that the button with a white picture of the car with bootlid open, which opens the boot remotely when you press it, would fail to open the boot using this button?

[Steviewevie]

If a 3 button key had been reprogrammed to be a sub key then I would imagine that the button with a white picture of the car with bootlid open, which opens the boot remotely when you press it, would fail to open the boot using this button?

Good question, I don't know.

[dave1]

If a 3 button key had been reprogrammed to be a sub key then I would imagine that the button with a white picture of the car with bootlid open, which opens the boot remotely when you press it, would fail to open the boot using this button?

Good question, I don't know.

So one would think that if all 3 buttons function correctly then the keys are "master" keys. So by checking if all of the buttons on the key perform the correct functions it would appear simple to ascertain which key/keys are actually fully functioning "master" keys.

[sparkystav]

No not necessarily

I've made two more spare three button keys for my car, so they cant be masters but all three buttons work.

Stav

[dave1]

No not necessarily

I've made two more spare three button keys for my car, so they cant be masters but all three buttons work.

Stav

It really depends on how one defines the term "master key". If the keys have the required number of buttons which function in an identical and correct manner then realistically they can be classed as "master keys". According to Lexus the "master key" works in all of the locks whilst the "sub" key (valet key) will not open the glovebox,boot or boot main switch.

Lexus supplied 2 x 3 button full function (master) keys and 1 x 2 button (sub) keys with new cars at the time and only use the terminology master or sub key. They themselves define the 3 button key as a master key and since they supplied 2 of them it stands to reason that Lexus call both of the 3 button keys masters. The transponders are identical in both the 3 button and 2 button keys, the difference being that the actual blade on the 2 button key will not fit the boot, boot main switch or glovebox and hasn't got the 3rd button to open the boot remotely in accordance with the "valet key" concept.

[Steviewevie]

Lexus's definition is referring to the day-to-day use of the key though, i.e. whether it can open the boot etc. What we're talking about here though (from the original posting) is key reprogramming, where the master key is defined as a key that can be used to reprogram another key.

A 2-button key that has been programmed as a "master" can be used to reprogram another key. A 3-button key that has been programmed as a sub key can't be used to reprogram another key.

Hence putting the key into the ignition and watching the Security light is the only true way to tell whether it's a "master" for key reprogramming purposes.

[dave1]

A 2-button key that has been programmed as a "master" can be used to reprogram another key. A 3-button key that has been programmed as a sub key can't be used to reprogram another key.

Hence putting the key into the ignition and watching the Security light is the only true way to tell whether it's a "master" for key reprogramming purposes.

Both the master and the sub key have the transponder chip which allows the car to be started. If the transponder chip is incorrectly programmed the immobiliser will not allow the engine to be started as the electronic code will be different to the registered ID code for the car. Does that not seem to imply that if the key will start the engine then it must have the correct programming on the chip. That would then imply that it could be used to reprogramme another key. As far as I can ascertain, the only difference between sub and master is the key blade and the difference in the number of buttons, sub keys are not programmed any differently to master keys.

Don't forget also that Lexus don't need a key to make and program a new key for your car.

[Steviewevie]

Both the master and the sub key have the transponder chip which allows the car to be started. If the transponder chip is incorrectly programmed the immobiliser will not allow the engine to be started as the electronic code will be different to the registered ID code for the car. Does that not seem to imply that if the key will start the engine then it must have the correct programming on the chip. That would then imply that it could be used to reprogramme another key. As far as I can ascertain, the only difference between sub and master is the key blade and the difference in the number of buttons, sub keys are not programmed any differently to master keys.

Don't forget also that Lexus don't need a key to make and program a new key for your car.

I think we might be talking at cross-purposes. As far as I understand, Lexus do need a master key to program a new key for you, if we're talking about the IS200/300. Other models may well be different. The programming instructions over in the Workshop forum will not work if you're not using a master key. If you lose all your keys, then as far as I know, Lexus's recommendation will be for a new ECU for your car.

There are other solutions about, yes, but will probably involve an auto locksmith.

Sorry but there is indeed a bigger different between master and sub keys on the IS200/300, otherwise the Security light wouldn't act differently with them, nor would the key progamming method detailed in the Workshop.

[dave1]

Both the master and the sub key have the transponder chip which allows the car to be started. If the transponder chip is incorrectly programmed the immobiliser will not allow the engine to be started as the electronic code will be different to the registered ID code for the car. Does that not seem to imply that if the key will start the engine then it must have the correct programming on the chip. That would then imply that it could be used to reprogramme another key. As far as I can ascertain, the only difference between sub and master is the key blade and the difference in the number of buttons, sub keys are not programmed any differently to master keys.

Don't forget also that Lexus don't need a key to make and program a new key for your car.

I think we might be talking at cross-purposes. As far as I understand, Lexus do need a master key to program a new key for you, if we're talking about the IS200/300. Other models may well be different. The programming instructions over in the Workshop forum will not work if you're not using a master key. If you lose all your keys, then as far as I know, Lexus's recommendation will be for a new ECU for your car.

There are other solutions about, yes, but will probably involve an auto locksmith.

Sorry but there is indeed a bigger different between master and sub keys on the IS200/300, otherwise the Security light wouldn't act differently with them, nor would the key progamming method detailed in the Workshop.

Quite possibly cross-purposes. What I have been saying is correct for my 2002 GS430 and I assumed all Lexus models would be same when it came to keys/transponders/immobilisers. If you lose all your keys,(with the GS anyway) Lexus can supply and programme new keys for you providing that you have the key number (which is supplied on a small metal tag with your keys when new). As far as I know my keys ( 2 x 3 button, 1 x 2 button) are the original keys supplied with the vehicle when new, as is the tag with the key number.

Interesting discussion though.

[chi]

Got both my new keys sorted for 20pounds in HK and lucky me, they both worked.

All i had to do was put transponder into new blank :)