dadoo

Bought a 1998 ES300 and found out I only have one (1) Valet Key, so I cannot make: Master Keys, Valet Keys, or use it to unlock the truck and glove box.
The dealer wants to install a new ECU and Master Key for $600 to solve the immobilizer problem.
I already have 3 transponder-chipped Master Key blanks from Ebay ($21) and had them cut ($15 each). But without being programmed they only unlock the doors.
From what I have read, the 'fixed' transponder code must match the 'programmed' code on a chip in the ECU.
Question: could I go to the bone yard and get *both* the matching ECU and Master Key ($75) from an identical car (make/model/year/part number), then install that ECU in my car and use the matching Master Key to program the three blanks for my car?

Because you do not actually turn the ignition key to program new keys (the bone yard would not operate any of my locks), could I simply use the bone yard Master Key/ECU combo to program my already cut blanks? That way I could keep all my existing lock tumblers. This sounds like a cheap and easy way to make Master Keys from a Valet Key.

LeX2K

Your logic is sound but are you sure no key turning when programming? Another gotcha is you're counting on the ECU being good and there is a key programming limit so if you're unlucky the replacement ECU won't accept all or any of your new keys. BTW there are services on Ebay that will program your ECU and return it with working keys.

dadoo

Lexus2000:
1) Yes, all the methods of programming just a key (not remotes or fobs) do not involve actually turning the ignition key. You just put in the Master, have it recognized, and take it out.
2) Yes, there is a limit to the number of keys you can have 'active' in the ECU. But there is also an erase routine you can use with one Master Key to wipe out the existing codes of all other keys in the ECU (this routine is used if you have a key stolen, you erase all other keys, then re-enter the ones you do have, so the thief cannot steal your car). Then you can add more keys. So I am banking on the bone yard ECU/Master Key were both in working order before the car was junked.
3) Yes, the Ebay ECU/Master Key service is available for $150 plus paying to get those keys cut. But I would rather save time (when my ECU is being shipped back/forth) by installing just the used ECU and programming the keys myself. ECUs are extremely reliable, so I am comfortable with a used one.

LeX2K

Sounds like you have it all sorted out.

dadoo

Lexus2000,
Just wanted to post this to the CL community to see if there are any holes in my proposal.
Hopefully there is no VIN matching or engine matching to prevent a used ECU/Master Key from operating.
This might be a fast easy solution to a fairly common key problem.

LeX2K

AFAIK there is no VIN stored in the ECU. Keep us updated.

Ace20Six

Yes please do update this thread with whatever works out in the end. I just purchased a 2000 ES300 a few weeks ago. The car came with (1) Keyless entry key and (1)Standard non keyless entry key.. None of them can unlock the drivers door manually. Looks like the door lock cylinder is a little damaged. I can only manually unlock the passenger door, also can not manually unlock the trunk if needed. Just today as I was turning the key in the ignition to turn the car off with the keyless entry key the housing snapped apart, and the key itself was still in the ignition cylinder. Luckily it wasn't stuck and I was able to remove it.

I have not had the time to contact my local toyota/lexus dealer to see how much new keyless entry keys are yet, but from just searching through the forum this seems to get pretty pricey. So much so that it may be cheaper to go with aftermarket remote start alarm, which I could also fit with a Lexus/Toyota style push button start system like newer cars have. I get up at 3am and it will be freezing soon at this time in the morning. Would like the car to be warmed up and defrosted by the time I get outside to leave for work.

Solidhit

I just bought my wife a 2004 ES330 that only came with a non factory key. The key opened the doors and started the car but didn't have the buttons to remotely open the doors. The dealer figured that to go to Lexus to have a key made would cost about $250 - $300 so we built that into the cost. When I went to Lexus I found out that the key cost $250 but the programing and cutting was an extra $125. I OK'd the cost and a few minuets latter the service rep came back to tell me that because the key I gave him was not programed, it was going to cost extra to start from scratch - to the tune of $495.25. I called the dealer and he picked up the extra cost but I found it incredible that it cost $500 to get a master key made. (incidentally, the non Lexus key still worked).

dadoo

I spent a lot of time on car-part.com trying to get a used ECU. However, there are 4 different part numbers listed for my 1998 ES300 (California/Federal, with Traction Control and w/o). So there were few which were correct... and none of those had a matching Master Key from the same car. Also, the very few boneyards which had any keys insisted on selling the steering assembly key socket with the key. So after wasting a lot of time, I decided to use the Ebay ECU swap for $150. It is too much time and effort to get a used ECU and Master Key.

With the Ebay swap I will be able to program my own Master Keys and so keep all the key tumblers.

So the bottom line if you only have a Valet Key:
1) order some blank Master Keys on Ebay
2) find a local locksmith that does 'center cut' car keys ($15-40 each)
3) if you remove the glove box you can see the ECU part number without removing the ECU
4) order the Ebay ECU with a Master Key
5) install the ECU and program your new keys
To make 3 Master Keys it will cost you about $250 total. Don't know any way around that.

speedkar9

I already made a video and entire thread on this whole lost key scenario.
You can simply hack in to the ECU's EEPROM chip and reprogram it to a virginized state. Then reprogram your new keys. No need to spend money on an ECU swap.

Full write-up here:
https://www.clublexus.com/forums/es-...apped-ecu.html


Note: If you have the 4ES or newer Toyota, the immobilizer chip is stored in a separate transponder ECU buried way inside the dashboard.

808mcv20l

I'm curious to know if you could have just used Techstream software to reprogram the ECU to accept your old master key.

speedkar9 had a video on virginizing the ecu, maybe you could have done it that way instead.

nm I now see that he posted the link to his video, yah if it were me I'd try his way first, but it is only for the technology savy individuals.

wmj259

I just tried looking into the Techstream method. Turns out this won't work, because to register more keys, 1 of the 2 MASTER keys from the replacement ecu are needed. If you don't have those then you would need to basically clear the eeprom chip to be able to reprogram new keys.

dadoo

One of my kids finally lost my last Valet Key to my 1998 ES300. I spent a whole month with this car sitting in the garage. Here is what I learned from this bitter experience:
1) for making new keys, go on Ebay and look up 1010keys in California. They are fantastic. Either get your Key Code from Lexus or send a cell pic of your Valet Key to them. For about $22 each they can ship you: an OEM Denso key, with remote buttons/battery, and make a very clean center cut. Trust me, this is a screaming deal!!
2) go on Ebay to look up Modulemechanics in Florida for your ECU re-flash. For $60 they can 'virginize' your existing ECU. If you have no keys, you can have 1010keys mail the cut keys to Modulemechanics and they will flash the new keys directly into your ECU, then mail back your ECU and keys. These guys are real wizards!!
3) if your ECU is bad (or like mine, will *not* accept new keys), go on car-part.com and order a used ECU with the exact matching part number. You can get these for around $45 with shipping. Have it sent directly to Modulemechanics. Then send your existing keys to Modulemechanics. They can program both your keys and mileage on the used ECU.

The ES300 models with the Immobilizer Chip on the ECU are pretty damn quirky. Lots of anomalies in this first-generation product.
I know there are how-to videos about re-flashing the ECU, but for $110-130 and one week for shipping, you can get *both* a functioning ECU and functioning Denso keys for your car.
This is the lowest-cost/fastest way to get quality 'cut' keys *and* a matching ECU.

wmj259

Thanks for the advice @dadoo.
I am trying to go on the DIY route as this would also be helpful to other DIYers if I am successful. My only issue with car-part.com is I would have to call a lot of people to find my ecu part number. Especially since its a U140e transmission. Expensive of them all. I got my ecu off of ebay for $80-90 (cant remember now) and with lifetime warranty. Only issue now is to virginize it, which from where I intern at, I have a friendly electrical engineer that can help.
Right now my current progress is hacking this eeprom chip. Hopefully I get this working in the next week. I need to get another key made.

Mauser

I have been going through this too. I tried the speedkar hack and was able to read the eeprom, and completely zero it out (all Fs) with pony prog. I am not able to write anything else back to it.