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Discussion Starter #1
I’m looking to get some information on what exactly can be done with Toyota’s ECU and how much you can possibly alter when reflashing, you guys seem to know the most when it comes to modifications and swaps so I figured asking here wouldn’t hurt.

I’m located in California, so I’m trying to avoid dealing with having to see a Smog Ref and jumping through a bunch of hoops so I can easily smog the car when its due.. I’m also going to talk with my smog guy and see what he says also.

(Short version)- I will be using a 2000-2004 Toyota Avalon ECU in a 2000 Lexus Es300, I want to know if the information on the Avalon ECU like Make and Model that’s stored in it can be altered to look like a 2000 Lexus ES300?

(What I’m attempting)- I have a 2000 Lexus ES300 with 3.0 1MZ-FE VVTI mated with U140E transmission that’s notorious for being weak. My car has been sitting for about a year with a dead transmission, I dropped the pan and there’s metal everywhere. First gear is completely gone, and it can barely move in reverse. The damage is so bad that I can’t even push the car in neutral.

I don’t feel like taking the chance of swapping in another used U140e transmission when they are notorious for going out, unless regularly serviced these transmissions are ticking time bombs, even though going that route would be the easiest. I considered rebuilding but after pricing the parts out its not worth it to me. Then I discovered that the 2000-2004 Toyota Avalon has the same 1mzfe vvti engine but has the much more reliable A541E transmission that was used with plenty of other NON VVTI engines.

I want to use my original VVTI 1mzfe engine and match it up with the A541E trans from the Avalon, I will use the engine harness and ECU from the Avalon also. My ES300 has a immobilizer but I think I have that figured out with the keys and such once I get the Avalon ECU. The only thing I’m not sure of is how my gauge cluster and HVAC controls will work with the Avalon ECU, both the Avalon and Es300 seem to have the same exact HVAC controls. I have to look over some wiring diagrams to double check, between the ES300 and Avalon with the same engine and same hvac controls the only thing I can imagine to be completely different in the wiring is between the U140E and A541E.

Far as I know California doesn’t seem to care what transmission you use, just that when doing swaps the engine has to be from the same year or newer and retain all original smog equipment, I’m not altering any of that and just swapping transmissions. However when I go to smog and they plug into the ODB port the ECU would read Avalon and I assume that is where I will have issues. I’m estimating $500-$700 for transmission, wiring harness, ecu VS the $1700 or so in parts alone to completely rebuild the U140E. Ive also been coming across entire 2000-04 Avalon donor vehicles that's cheaper than rebuilding my original trans. I think going the Avalon route is my cheapest option, if I didn't have to smog the car this wouldn't be an issue, unfortunately I have to deal with smog natzis.
 

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I thought the transmission had a separate controller, rather than being built into the car's ECU. I could be wrong about that. There is also the possibility that they use a similar interface so it may just be plug and play
 

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Discussion Starter #3
No, unfortunately it's all controlled by the ECU. Honestly I may just be over thinking this, I will know for sure when I talk to the smog shop. I'm not sure what info is displayed/read or what's being sent to the DMV when they hook their computer up to the ODB port so this concern is what triggered this post to being made..
 

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Discussion Starter #5
Short answer, no.
Thank you.

I suppose the real question is not the make and model but rather if the VIN# can be changed in the ECU as I’m sure the make and model are tied to that rather.

I know when I used to frequent a few GM/LSX based websites when I did some engine transplants there were a few people that could change VIN# with either HPTuners or EFI Live tuning software. I was curious if the same could be done here with a Toyota ECU.
 

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Thank you.

I suppose the real question is not the make and model but rather if the VIN# can be changed in the ECU as I’m sure the make and model are tied to that rather.

I know when I used to frequent a few GM/LSX based websites when I did some engine transplants there were a few people that could change VIN# with either HPTuners or EFI Live tuning software. I was curious if the same could be done here with a Toyota ECU.
Unfortunately there is no getting around the "short answer, no" with a longer answer, no matter how strongly you would like to or how strongly you believe it should be possible.

Toyota ECU's before 2005 cannot be re-flashed, except for the immobilizer chip, that can be re-flashed with a virgin dump. This requires that you either solder leads to the immobilizer chip or desolder it from the board. It is not possible to change anything in the ECU's calibration file which resides in the main EPROM, which includes the VIN and the calibration ID. Your ECU has a closed architecture with a write-once Toshiba EPROM. To reprogram the EPROM you would have to de-solder it from the board and clear it using x-rays. Even then, the instruction set and format of the data is unknown and remains a very closely guarded secret. There is some very obscure information available on these ECU's but it is not readily accessible or usable.

Beginning in 2005 Toyota rolled out a new ECU architecture based on the Renesas v850 processor. This architecture complies with the SAE J2534 standard, mandated by the EPA, that requires ECU's to be field-flashable and requires the manufacturers to provide the tools for doing so. Even so, working with these ECU's is no cakewalk and requires specialized tools and knowledge. Check the thread "2GR-FE ECU Tools and Techniques" to get a flavor for this.

In the last year or two - I forget the launch date, time flies - HPTuners has initiated support for a very small number of Toyota ECU's , literally just a handful of vehicle models. These are all 2005 and later vehicles. Your ECU is not one of them. HPTuners appears to have absolutely no plan to extend their support to other models and even if they did there is absolutely no way - barring miracles and acts of God - they could support ECU's with the Toshiba architecture.
 

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Looks like your path forward will be to make the swap official by visiting a BAR referee inspection and getting the sticker that makes your ES300 officially an Avalon from smog inspection point-of-view. Since you aren't altering smog equipment this should not be a huge deal. Subsequent bi-annual inspections will be done like normal (OBDII plug-in only) with your car treated as an Avalon.
 

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Discussion Starter #8
Thank you for explaining and dropping that bit of information. I appreciate it

Looks like your path forward will be to make the swap official by visiting a BAR referee inspection and getting the sticker that makes your ES300 officially an Avalon from smog inspection point-of-view. Since you aren't altering smog equipment this should not be a huge deal. Subsequent bi-annual inspections will be done like normal (OBDII plug-in only) with your car treated as an Avalon.
Yeah you may be right, it’s not a huge deal breaker or anything it’s just that if it was possible for me to avoid seeing a referee then I would have preferred that. I talked with my usual smog shop and he said he couldn’t say for certain so basically only way to know would be to just find out whenever I completed everything. I have to smog the car this year in June so I’ll give it a shot, and if it doesn’t work out I’ll go see the ref and get it all set straight.
 
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