Does anyone know why you NEED your master key to program a new one? I work in the computer field and that just doesn't make much sense to me. It has got to be possible to take a blank master and reprogram it with the image in the ECU provided the key can work with your car.

Am I way offf?

G

 

You have several different systems out there.

1) The models that require a Master Key in order to add in more keys. You can't open the programming mode with a valet key. This is to stop the valet from getting copies of your key and programming them in and then stealing your car later. The chip which contains the immobilizer data is isolated so you can't communicate with it using a scan tool. In lost key situations or valet key only situations Lexus has to replace the ECM and then program in new keys. Only when an ECM is brand new and first installed does it accept new keys. Locksmiths can do it a different way. We reset the IC900 chip so the ECM thinks it is brand new... then we program in the new keys. This is a 16bit ECM.

2) The models that require a Master Key in order to add in more keys. Same thing as #1 for valet keys. However, the chip is no longer isolated and can be reprogrammed with a scan tool to accept new keys even if all of the keys are lost. This is a 32bit ECM.

3) Some newer models don't have the OBP option and all keys have to be added in using a scan tool.

4) Then you have the models that need both a scan tool and a new module if you lose all of the keys.

Gotta love Lexus and their key systems!

Take care,

Tami

 

damn.

that's an answer and a half!!

Good job Tami!

 

Also you can only program up to 4 master keys per car

 

to me i think maybe they want to make it security and not able to let people just make too many duplicate keys for the car

 

See that is technically who you ask. I have an alarm guy, who just opened up my ECM, erased every damn key that was in there. And programed back in only the ones I have.

 

Did he reflash the ECM or did he just erase all of the keys except for one existing master key and then use that key to reprogram in your other existing keys?

Tami

 

What if you lose your master key and your car gets stuck in the garage? How can you get another key? Cant you send the vin and title to the dealer and oreder you a key?

 

What year and model are you talking about?

If it does have the transponder system then you would either need to tow your vehicle to the dealer (which can be an issue if the tow truck can't get to your vehicle in a garage) or hire a locksmith who can come to your vehicle and make a key on the spot.

The problem with just getting a key at the dealer is the programming so your vehicle will start.

If it is an older model without a transponder system then it isn't that big of a deal. The dealer can order a key for you or you can order a key online from a locksmith.

Tami

 

2000

 

GammaLex,

Are you dealing with that situation right now? More than likely, if it is a 2000 model you have a 16bit ECM which will require the dealer replacing the ECM or you can email me for details on reflashing the ECM.(you would have to remove the ECM and ship it) Option 2 is a lot cheaper then having the dealer replace the ECM.

tcalhoun@cfl.rr.com

Take care,

Tami

 

He completely reflashed the entire ECM. I was freaking out for a while cause he went to test the keys to make sure he deleted them, and none of them worked. Then he just picked up the hex codes for each key, and put them back in. Needless to say I was freaking out for a while, especially since Lexus told me that you may need a new computer if you erase all of them from the ECM or loose all of your keys. When I told my alarm guy this, he laughed. He said that a pro theif will drive the lexus away with his own key, after they reprogram the ECM.

 

We reflash ECM's all the time when there is only a valet key or no existing keys. Saves the Lexus owners a lot of money!

Tami

 

Yea saved me a ton. I know this guy personally so technically it's a hookup. Lexus wanted $255 for another key, and $45 for the programing. Then they checked my car and said all memory slots were full and it would cost me $295 to get them erased.

My guy, $100 for the key, cut and programmed. And free ECM reflash. Now I am guaranteed that I am the only one with keys for my car.

Oh and by the way, Lexus states that if you loose all of your keys, it will be $2500 for a ECM replacement/reflash. Well at least that is the crap they were feeding me when I told them I am not interested in their services.

 

oy vey......STOP THE INSANITY!!!!!


I got my GS4 with one key and I needed spares...I simply gave sewell my VIN# and proof of ownership of the car and voila, within a week I had spare keys to my door

NOW, with those spare keys they WILL NOT start the car until they are programmed INSIDE the car....I have the programming instructions somewhere....