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ECM/ECU replacement questions

Discussion in '1st Gen. Tacomas (1995-2004)' started by Tacomaduder, Mar 20, 2017.

  1. Mar 20, 2017 at 3:26 PM
    #1
    Tacomaduder

    Tacomaduder [OP] Member

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    I had a crank but no start problem on my n my 99 6 cyc 3.4. After giving up trying to fix it myself, I took it a mechanic. He said the ECU is dead and it would cost $2500 to replace. Seemed high to me so I towed it back to my house and took out the ECU. Water was getting to it. The circuit board is corroded and looks shorted out. I don't think mine can be repaired.

    Can anyone recommend a place to purchase a reconditioned one? Also, I've seen some places that sell ECM/ECU state that they will program the VIN and mileage into the new one. Is that necessary? Would one off of ebay work? Does the VIN need to match to pass emissions testing or something like that? Any advice would be appreciated
     
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    #1
  2. Mar 20, 2017 at 3:30 PM
    #2
    TashcomerTexas

    TashcomerTexas My truck is a whiner

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    LMAO $2500 for a 99 ECU? What a jackass.
     
    cruxofthebisquit and wilcam47 like this.
  3. Mar 20, 2017 at 3:34 PM
    #3
    anothernord

    anothernord Well-Known Member

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    I have one for sale from a 2001 3.4 auto 4x4 for $100. I'll check to see if it's compatible.

    There's not really such thing as "reconditioned" ECM. They either work or they don't.

    The mileage is stored in the gauge cluster, not the ECU. As far as the VIN, that shouldn't matter for most states, as long as you pass emissions and have the correct VIN on the body/frame, you should be fine.
     
    wilcam47 likes this.
  4. Mar 20, 2017 at 3:37 PM
    #4
    Wyoming09

    Wyoming09 Well-Known Member

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    I have done business with ECM Depot there down in Texas

    I beg to differ they can be reconditioned depending just what the damage is

    Now maybe the newer Trucks need the ECM programed but none of mine in your era needed it done.

    Now prices might have changed but the last New ECM I priced at the Dealer was @ $900.00 it was a few years ago.

    I picked up 2 ECM`s at Local yards for $100.00 each

    You do need to buy a ECM with the same part # that yours is to make things easy

    Be nice to know where you are??
     
    Tacomaduder[OP] likes this.
  5. Mar 20, 2017 at 3:48 PM
    #5
    TashcomerTexas

    TashcomerTexas My truck is a whiner

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    Yes look at the part # on your ECU and google it. It's real simple, it'll bring up various Toyota sites and distributors that sell the part #. Find the one that's the cheapest.
     
    Tacomaduder[OP] likes this.
  6. Mar 20, 2017 at 3:54 PM
    #6
    anothernord

    anothernord Well-Known Member

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    I would never, ever buy a "reconditioned" ECU.

    Besides cleaning junk off the terminal pins (which would mean you have bigger problems), internal ECM/IC problems are really hard to diagnose. Unless it's something totally obvious like an exploded capacitor (common DSM problem), that's really simple to replace. Even if you did have the required equipment, and the time it takes to diagnose an issue within the circuit board, in our world of Toyotas, it'd just never be worth the cost, especially with used replacements being so widely available and low-cost.

    I agree with finding one with the same part number, though.
     
    Tacomaduder[OP] likes this.
  7. Mar 20, 2017 at 4:24 PM
    #7
    Tacomaduder

    Tacomaduder [OP] Member

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    Thanks everyone!

    anothernord: you wouldn't recommend getting a "reconditioned" ECU but what about just a used one?
    The one I need is PN# 89661-04450

    I agree it's not worth the time to do any electrical testing on the ECU. I'm an electrical engineer. I design circuit boards.
    I always try to at least a quick visual scan to fix electronics before throwing them out. More common than exploded caps, I find surface mount fuses are blown. They look just like resistors and capacitors so they can be hard to spot. This unit had none of the easy fixes.
     
  8. Mar 21, 2017 at 1:40 AM
    #8
    Wyoming09

    Wyoming09 Well-Known Member

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    To each there own !!

    I send circuit boards out all the time to be rebuilt a ECM is the very same thing.

    When it comes with a Lifetime warranty for anything but water damage and costs @ $300.00 as compared to $3000.00 for new

    If it is the difference between having a pile of scrap or something that works I will go something that I can still use
     
    koditten likes this.
  9. Mar 21, 2017 at 11:23 AM
    #9
    anothernord

    anothernord Well-Known Member

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    Right, that's what I'm recommending. A used replacement that was pulled from a running vehicle. eBay or these forums would be my go-tos to source one. Or a local junkyard.
     
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  10. Mar 21, 2017 at 12:35 PM
    #10
    Tacomaduder

    Tacomaduder [OP] Member

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    I ordered one on ebay to get my truck up and running as soon as possible. I think I'm going to try to get the old one reconditioned. The company SIA Electronics seems to only charge you if they can fix it. You only risk the shipping cost. If they fix it, I'll sell it on ebay
     
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  11. Mar 26, 2017 at 8:21 AM
    #11
    Keep on Truckin'

    Keep on Truckin' Well-Known Member

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    Keep the old one after recon.as a spare you know fits your truck !
     
    Tacomaduder[OP] likes this.
  12. Mar 26, 2017 at 3:13 PM
    #12
    Tacomaduder

    Tacomaduder [OP] Member

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    Popped the new ECM in last night and started up like a charm
     
  13. Mar 20, 2018 at 10:53 AM
    #13
    99 taco

    99 taco New Member

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    Looking for ECM for 99 Tacoma 4x4 MT 89661-04450 is the ECM number
     
  14. Mar 20, 2018 at 12:10 PM
    #14
    mwrohde

    mwrohde Well-Known Member

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    Where in the truck is the ECM? Is ECU and ECM the same thing?
     
  15. Mar 20, 2018 at 1:52 PM
    #15
    99 taco

    99 taco New Member

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    Behind glove box and vent tube. You’ll see the plugs for it and 2 Philip screws hold it in
     
  16. Mar 21, 2018 at 11:01 AM
    #16
    Luv my yota

    Luv my yota Well-Known Member

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    Believe it or not a Denso engineer on the lexus forums says the computers are bound to fail in a way or another. I read through a huge thread about them selling upgraded caps, resistors, and fuses that look like diodes and the vehicles were picking up power that did the refurbishment. It makes sense as ours take alot of vibrations and water from the wiper gutter, transformers for power companies go out all the time and they are very expensive, most wouldn't think that this is wear and tear.
     

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