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4Th gen ECU swap questions

Discussion in '4th Gen 4Runners (2003-2009)' started by 4x4s4life, Aug 31, 2023.

  1. Aug 31, 2023 at 6:57 AM
    #1
    4x4s4life

    4x4s4life [OP] New Member

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    Hello,

    I am going to replace the ECU soon in my 03 limited overland build. There are two different ones listed on the Toyota site.

    1: has anyone done it?

    2: how to determine which of the two is the correct computer for this thing? Identifying numbers on the old one or something?

    3: I've seen where a dealer has to program the VIN after install to disable the ignition security feature, is this true?


    I am hoping you guys can help me here.

    Thank you
     
    RonT4R likes this.
  2. Sep 1, 2023 at 5:37 AM
    #2
    4x4s4life

    4x4s4life [OP] New Member

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    Nobody has any experience with this on here?
     
  3. Sep 1, 2023 at 8:06 AM
    #3
    xtremewlr

    xtremewlr New Member

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    Why are you replacing the ECU?

    If the OEM ECU has failed, what caused the failure? Replacing it without fixing the cause will potentially cause the replacement to also fail.

    Always try to exactly match the part number off the OEM ECU for the replacement ECU.

    You will most likely need the replacement ECU programmed with your VIN, yes.
     
    RonT4R likes this.
  4. Sep 2, 2023 at 5:22 AM
    #4
    4x4s4life

    4x4s4life [OP] New Member

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    I have been doing a rolling restoration as I build this thing for overlanding.

    I am replacing the ECU because at this time it is 20 years old and will fail likely around the 25 year mark-ish from what I have seen. That's not written in stone as they say,but it's closer to failure today than it was 5 years ago for sure and replacement now will save me a lot of trouble later, 500 miles from home and 50 miles in the boonies.

    We can put 400,000.00 in one of these machines and a 500-900 dollar ECU makes it a very expensive paper weight. Not getting rid of it so I have been replacing known failure points as I go. Eventually it'll go to a kid or grandkid.

    So, the P/N is on the top or where on the ECU? Pretty hard to see anything in there.
     
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  5. Sep 2, 2023 at 10:50 AM
    #5
    xtremewlr

    xtremewlr New Member

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    These are not known for random ECU failures. You're wasting time and money replacing it as preventative IMO. But if you insist, then you really need to pull the current ECU to see the part number.

    Note that I have over 338k miles on my 03 4runner with the V8. Zero ECU problems. They only have issues if you drown them or start messing with tunes and manage to brick them. Random failures are very rare.
     
  6. Sep 3, 2023 at 9:49 AM
    #6
    4x4s4life

    4x4s4life [OP] New Member

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    How many years do they last?

    How many miles do they last?

    Will you sell yours after the ECU dies?

    These answer matter quite a bit, especially the third one. And that is the difference here.

    The vast majority of them end up in a junkyard due to rust, accidents or piss poor maintenance.

    Thanks for your input.
     
  7. Sep 3, 2023 at 1:05 PM
    #7
    xtremewlr

    xtremewlr New Member

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    What is the difference where? You are assuming I would sell. No, I would repair or replace the ECU as needed. How many miles or years will they last? Unknown, since there are still many on the road today that haven't had ECU issues.

    You didn't state what motor you have, that makes a difference in the available ECUs for the vehicle.

    Looking at ECUs for my 03 V8 Ltd 4x4, there is either a new OEM ECU for $923 or a reman ECU from Toyota for around $550. There are 4 different ECUs listed, 2 new or 2 remans. 2 of them are for 2WD vehicles and technically would not work in a 4WD vehicle, if you retain the stock transfer case. I should be able to use the 2WD ECU in my vehicle as I no longer have the stock, electronically shifted transfer case that is failure prone due to not being used by most people and why the original one in my truck failed. I now have a manually shifted version from an FJ Cruiser, so that should open up my ECU options to the 2WD variant as well.

    More importantly than the ECU, have you done anything with the transfer case yet? The stock ones are prone to having the shift solenoids fail if they aren't used on a regular basis. If you bought the vehicle used and the PO didn't use 4WD, then you could potentially have an issue there, even if they are working now. Mine worked for a short time and then failed due to poor repairs by the PO and failed shift shaft seals allowing gear oil into the solenoid housing. I replaced it with a 2011 FJ Cruiser manual shifted transfer case and eliminated that potential issue altogether. Something to think about.
     
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  8. Sep 3, 2023 at 2:16 PM
    #8
    pastoreater

    pastoreater New Member

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    You want a new ecu because eventually the capacitors start leaking and then corrode is my understanding. But we don't know when dealer OEM parts were manufactured, could be new old stock. From my perspective the solution is stand alone ecu or find a specialist to refit components on the boards of a spare and your original.
     
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  9. Sep 3, 2023 at 3:20 PM
    #9
    xtremewlr

    xtremewlr New Member

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    Well, that was my point originally. The K line ECU from Toyota, which came out in something like the late 90's and is in the 4th gen 4Runners, is not known for having the capacitor issues of the early 90's ECUs. And that is per a buddy of mine that is a Toyota Master Tech. No notable issue with them at all. But, he want's to replace it. Not worth the effort im my opinion but I'll try and help him determine the correct ECU for his application.
     
    MI-FL off roader likes this.
  10. Sep 8, 2023 at 5:40 AM
    #10
    4x4s4life

    4x4s4life [OP] New Member

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    I think you mistook my original post.

    I wasn't asking for an opinion, which you obviously think yours is of superior value. Only asked a couple of bullet points and they were pretty simple.

    Figured out which P/N I wanted, so it's all good.

    Thanks for your 2 cents though, and have a fantastic day.
     
  11. Sep 8, 2023 at 8:23 AM
    #11
    xtremewlr

    xtremewlr New Member

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    I didn't mistake shit.

    You didn't like being told that you're wasting time and money. It's not that my opinion is of superior value, that's like saying your asshole is worth more than mine. You just happened to take offense to it because you don't like being wrong.

    Nevermind the fact that I still gave you the information that you were looking for to get a replacement ECU.
     
    Libagui likes this.
  12. Sep 8, 2023 at 8:33 AM
    #12
    Libagui

    Libagui New Member

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    Where do get this information from?. I've never seem nore hear about a faulted 4runner ECU. You are over preventing.
    Only bad known failure on this engined is the head gasket on 2006- models.
     
  13. Jul 9, 2024 at 5:12 PM
    #13
    Santidelart43

    Santidelart43 New Member

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    can you ask you toyota tech friend about my issue?
    No start no crank when turning key, all normal lights on dash, new battery, new starter, new neutral position sensor, new ignition switch. If i send direct power to exciter on starter cranks but no start (key on acc). I dont hear click or nothing just plain no start no crank.
     
  14. Jul 12, 2024 at 4:53 PM
    #14
    Ralph Blake

    Ralph Blake New Member

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    This is something new for me to start worrying about since my 16 year old 2008 4Runner now has a little over 10,000 miles.
     
  15. Jul 12, 2024 at 5:03 PM
    #15
    RonT4R

    RonT4R New Member

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    I was under the impression from talking with several Toyota Service guys that certain sensor and switches in the engine and transmission are linked to the original ECU and if you replace the engine, transmission or ECU those sensors either must be transferred or remapped to the new item. Not sure but good luck and I want all the following info after this……my 4Runner is nearing 285k so replacement info will be helpful.
     
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  16. Jul 13, 2024 at 9:54 AM
    #16
    xtremewlr

    xtremewlr New Member

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    Did you guys even read the thread? ECU failures are EXTREMELY UNCOMMON for the 4th gen 4Runners. Why are you worried about this??
     
  17. Jul 13, 2024 at 10:19 AM
    #17
    Ralph Blake

    Ralph Blake New Member

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    Why shouldn’t I worry?
     
  18. Jul 13, 2024 at 10:24 AM
    #18
    xtremewlr

    xtremewlr New Member

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    I'll say it again....

    ECU failures are EXTREMELY UNCOMMON for the 4th gen 4Runners.

    It's like worrying about getting a flat tire or that you might get in an accident. Do those things happen? Yes. But in your vehicle's lifetime, they are hopefully extremely uncommon. There are better things to worry about, like doing regular maintenance on your vehicle that you are constantly over looking.
     
  19. Jul 13, 2024 at 10:37 AM
    #19
    Ralph Blake

    Ralph Blake New Member

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    I am just joking hey my 4runner is 14 years old and has only 10,185 as of today.My 4runner mileage 07132024.jpg.jpg
     
  20. Jul 13, 2024 at 10:42 AM
    #20
    xtremewlr

    xtremewlr New Member

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    And mine is 21 years old and has 347672 miles on it as of today. ECU problems are a non-issue.
     
  21. Jul 13, 2024 at 11:00 AM
    #21
    Ralph Blake

    Ralph Blake New Member

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    Well something thats out of the ordinarily could happen, like if i could drive my 14 year old 4runner to say Proxima Centauri if there was a road to drive there on,as it's only about 4.3 light years from my home then i would have around 25 trillion miles on it now that is something to keep in mind and worry about.
     
  22. Jul 13, 2024 at 11:03 AM
    #22
    jeepster09

    jeepster09 "Old"-Member....

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    A work in progress.....
    There are no moving parts in ECU. They work or they don't. A new one has just as much chance of failure as an old one. You are wasting your money on replacing it. Water pumps, starters, alternators, other MOVING parts are more likely to fail.
     
    Last edited: Jul 13, 2024 at 12:27 PM
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  23. Jul 13, 2024 at 11:17 AM
    #23
    Ralph Blake

    Ralph Blake New Member

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    If you could find one from a wrecked 4runner and it was cheap having it might be a good idea, i agree i have a lot of really old electronic's and they still are working so the chances of my 4runners ECU failing soon is not likely to happen most new electronic items fail in the first 24 hours of service.
     

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