jehmin

Hello ALL
This is for those who may not know by now but.
You can indeed use a used ecu on some lexus vehicles with a push start "smartkey"
-No need to "clone" or change eeproms
-Requires Masterkey linked to the Smartkey module or Immobilizer.

Directions:
First disconnect Battery
Take out ECU + Swap for new one.
Next hook UP battery
use a paper clip or jumper or short OBDII ports 4 and 13.
HIt start button twice with brake depressed ( Not pressed, dont start engine) Ignition On engine off
Wait 30 minutes all lights blinking on dash.
Come back after 30 minutes hit the start once depressed to shut off.
Then start car. Turn it back off. Then hit start button twice brake depressed
Hook up to Techsteam and change to your vin number.
Odometer reading should be the same as when you started
Now you can start the car and everything should be working.

If this didnt work you will know because car will not turn on. It will try to crank. Or turn on and stop. Make sure you have a charged battery when performing this.

Notes:
ECU does not contain odometer numbers
ECU is linked to the smartkey or immobilizer module and this will require original keys.
Its not a ECU Refresh like with a code on TS
This is easier than changing eeproms on the ecu
Also the part numbers dont have to exactly match ( mileage may vary on this one)
OLD ECU will forgotten and will not plug and replay. This process must be conducted again to use.

Special Thanks to SpeedKar99 and George Melnik
Your automotive knowledge contributions are well appreciated.
Check out their youtube videos for more in depth tutorials .

JorisV

How about the connection with your auto transmission. My ecu keeps asking for a compensation code. But I'm unable to retrieve it. (Ref. Lexus GS300 2007)

Yw1011101

Hey, thanks for the info man. It helped me quite a bit. I have a question, do you know if the changing VIN using techstream step is necessary? because it wasn't shown in the George Melnik's video.

Also when you say "the part numbers dont have to exactly match", does that mean ecu from same gen could work? I have a 2005 IS250 A/T ECU, and I want to try put a 2011 IS250 A/T ECU in my car. Would it work? Thanks in advance!

jehmin

IM not sure on that one but you also have to make sure its RWD or AWD
If its free id say try it out and let us know. Im leaning on the NO because the 2011 might have some newer features the 06 does not.
WHats wrong with your current ECU? TRans Problem?

Yw1011101

Thanks for the reply! I know it's been a while. I just tried on the 2011 ECU on to my 05, the result is crank over and over but no ignition. I actually gathered some information elsewhere it seems that 05-08, 09-10, 10-13, 13-16 are group together. So if the ECU is in each subgroup, then it might work. It was something like the denso chip number. I got this information from a ECU remapping site, but I didn't try it. It might not be true. I ended up got a same year 05 ECU.

And yeah, my car have rough downshift from second to first issue.

jehmin

TO start im not a mechanic, I might not know what im talking about at all and you probably shouldnt take my advice.
I think your original ECU was OK personally. I have a spare ECU for my 06 RWD IS250. I also tried swapping and swapped back.
Iv been there with the Trans Issues. Thats exactly why I asked about the Trans. I wouldn't be surprised if you have a stuck in 3rd gear problem.
I have an entire write up with photos on how to diagnose it somewhere.
I mean the WORKS ecu pinouts resistance readings for the solenoids and everything.
There is No one thing that is gonna fix it.
However you should start with a drain and fill or drop the pan, clean or replace filter. while your in there take some resistance measurements from the valve body of the solenoids. if there is a problem replace solenoid. Then check the resistance value of the solenoids from the ECU. If there is a problem from the ecu to the solenoids,, there could be a wire problem. ECU to Trans. ( this wire) Not Internal Wires of the trans to the solenoids.
I chased this problem down the biggest rabbit hole like you would not believe.
Changed solenoids.. However sometimes this might work if you havent done too much damage to the trans already.
Didnt work for me then I got the trans replaced with a 08 with lower miles.
Then.,... another issue which was more like a hiccup happened and one of the wires from the ecu to the trans was bad.
So that wire was spliced in. Meaning instead of changing the entire wiring. I hooked up one wire into the existing wire and ran it down to the transmission making the connection which was then kind of wonky. This wasnt there before the trans change. Why it happened IDK.
Trans was installed by someone else but the rest of the work was done by me.
I dont think you need a re calibration for the trans either. I feel like this is one of those jokes mechanics use to throw something at the problem that will never fix the issue but make you spend money.

Let me know how your project goes and try to find my post for the tranny issue you will be surprised on how much detail iv gathered.

See Below
https://www.clublexus.com/forums/is-...ial-guide.html

Yw1011101

That was quite some work, man. I'm glad you got yours fix. It's such a rare thing you actually found the root problem and got it fix. Good work!

I actually got a question. So I ended up got another ECU from the same year 05 and exact same part number 89661-53670. I went through the exact procedure as your wrote for reprogramming the ECU. The result is crank over and over but no start.

So I started by bringing the battery to home and charged it to 13.1V. I swaped the ECU, connect the battery, put paperclip between pin 4 and 13, press the start button twice without break, dash light flashing, timer for 30 min, then turn off the car, remove paper clip, then try start the car. The car would only crank over and over but no start. Did everything I did sounds about right to you? I don't have a TechStream so I can't do the change VIN step. In your experience, could you car start before the input VIN step? And does the crank but no start mean the handshake is failed or could it be some other issue? Did your car start right away after 30 min? Do you think I should try to ran it a little longer?

So I'm stuck at the reprogmming ECU step. Don't even get to have all the fun with the tranny stuff. hahah..

Any advice? Many thanks again!!

DUBZ008

What do you mean by requires masterkey linked to the smartkey module or immobilizer? are you talking about the one that's currently linked to ecu in car that doesnt work. or the smartkey linked to the new ecu thats gonna be installed. why would happen if i got a ecu from scrapyard without the keys linked to it.

jehmin

The SmartKey for the car info is actually stored on a different computer under the dash and not the ecu.
You can use an ECU from the scrapyard

Rriley77

where under the dash is this box? I have the same issue. Trying your procedure with the TS vin change, but asking just in case.

DUBZ008

hey i dont know what your situation is, but if it's similar to mine where i had to replace my ecu for same one and needed the key to work on it. Theres a way you can learn your original smart key (push button start) to the new ecu. When you first swap ecu's, when you try to start the car with your old key. it will crack but no turn over. what you need is to trigger the 4th and 13th pin on obd port. this will put the car into diago mode, you will have to leave it there for 30mins, then use your key to start and your done. theres videos on youtube that show this procedure.

Rriley77

I did it that way, but wasn't sure if it was 100% the same bc those showed transponder key and it didn't work for me. This has been since Nov. of last year, I have since gotten a c413a? "Thing", create the adapter to allow read and write to the eeprom, but I want to make sure I do everything entirely correct. I'm no mechanic and I have a regular consumer's experience, minimal in depth experience and zero computer/ecu experience. So I've had to educate myself enough to complete it properly without full understanding of the concepts. So it was a while ago, I am presently charging my battery fully to go at it again before possibly tearing apart the inside, and creating variables. I do have TechStream 16.20 I think, so more I'm prepared. Will update on if the procedure in this thread with the TechStream vin after after the 9 and 14 pin jump. Previously, I was wandering without TechStream, busted versions of TS, etc. I will let you know how it goes though.

DUBZ008

what car year and model are you driving currently. and what happened that needed you to link key. ( did you swap ecu's? or something else.) If you have fob key and all you did was swapped ecu's, this key learning video i posted will work 100% as i already did mine on gs300 2006 awd.

Rriley77

07is250
swapped ecu