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2003 Prius Hybrid ECU

Discussion in 'Generation 1 Prius Discussion' started by wafflefries1, Jul 11, 2019.

  1. wafflefries1

    wafflefries1 New Member

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    Okay, so I drove my 2003 Prius to Alabama last week, and it broke down on the highway right when we got here. It has around 160k miles on it at this point.

    So after a lot of hassle I got it to a dealership and they informed me that the ECU in it is bad and that it would cost me 5k to replace. I bought the thing for 2k, and I'm not sure what to do at this point since I don't have a vehicle.

    I've read that ECU replacement is as simple as busting into the glove box dash area, but I'm not sure about two things.

    1: If I buy it used, will I be able to reprogram it manually, or does it have to be new.
    2: I can't find any info on reprogramming it in general, so would I need some proprietary board, or will the car do it automatically?

    The dealership wouldn't provide me with any additional error codes, so I can either find a way to fix it that way, or sell it for scrap. I'm not sure how to proceed, and the dealership is annoyed at me leaving it there for a whole week.

    Thanks a lot-
     
  2. Brian in Tucson

    Brian in Tucson Active Member

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    Obviously you're not gonna put $5 grand into your Prius. There's one ECM on Ebay, I don't know the answer to your questions. Probably Chap knows the answer and will join in. Things like the ECM are physically easy to replace, you can do it with a minimum of tools.

    2001 2002 2003 TOYOTA Prius Hybrid Electronic Control Module ECU # 89981-47063 for sale online | eBay

    I guess I'd ask the service writer at the dealer if they would be willing to install a used ECM if you can procure one. The people on the Ebay ecm might be willing to overnight it to you for a fee.
     
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  3. Patrick Wong

    Patrick Wong DIY Enthusiast

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    1. There are many ECUs - exactly which one is alleged to have failed?
    2. How much have you paid for the diagnosis? You should have received a service invoice with the DTC listed.
    3. Depending upon which ECU needs to be replaced, you may be able to replace it without any programming - or some programming may be needed to synchronize it with the other ECUs.
    4. If this is an engine no-start issue, the remedy could be as simple as cleaning the throttle body interior.
    5. Obviously it makes no sense to spend $5K on this. Once you determine which ECU actually needs to be replaced (if any) then it would make more sense to buy a used unit on eBay and install it yourself.
    6. A Toyota TSB discusses an engine no-start issue having to do with a downlevel engine ECU not allowing sufficient time for the engine to start. Perhaps this is what your dealer is referring to. However, a subsequent finding is that it is sufficient to clean the throttle body interior, so obviously that should be tried first. Do not drown the throttle body in cleaning fluid; instead spray the throttle body cleaning fluid on a clean cloth and use the cloth to scrub out the throttle body interior and throttle plate. You can rotate the throttle plate by hand to access the edge and the bottom. Then disconnect the 12V battery to clear the fault codes for a few minutes, then reconnect and see what happens.

    Good luck.
     
    #3 Patrick Wong, Jul 14, 2019
    Last edited: Jul 14, 2019
  4. wafflefries1

    wafflefries1 New Member

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    Thanks so much!

    I had a lot of issues with the dealership, and they did not keep track of the diagnostic codes for some damn reason. That being said, I finally contacted the person who did the work, and it is the P3000

    So today I ordered the correct ECU, and am planning to install it myself. I've read that they must reprogram it, and that it will only run me about $150. It's pretty hilarious because I found them new for $880 from Toyota. So that would have been $3900 for programming it and labor. Ridiculous.

    Anyway, I should have the part this Wednesday or Friday. I've seen a few posts about the dash disassembly, and I'm going to try those. If you guys know any definitive guides on doing so, I'd appreciate it.

    My only two worries are being shocked(I'm disconnecting the 12v), fitting the ECU in/the bracket mounting, or this used ECU being DOA.
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    definitive guide: get the factory repair manual info at techinfo.toyota.com

    I think that DTC P3000 is a battery control system malfunction. The potential fault areas would be the high voltage traction battery and the traction battery ECU. Neither of these are in the dashboard.
     
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  6. ChapmanF

    ChapmanF Senior Member

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    P3000 is just a code the HV ECU reports to tell you that the Battery ECU has reported a problem to it. Whatever codes the Battery ECU is reporting are the ones you really want to see, and will tell you what problem(s) the car has. Focusing on the HV ECU because it relayed a message to you is like shooting the messenger.
     
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  7. wafflefries1

    wafflefries1 New Member

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    Okay so I battled with the dealership to give me the actual diagnostic codes, and it took them two separate tries over the course of 3 days (in two separate weeks) to get the right answer for me.

    Turns out -- it's the inverter.

    So, I talked to the mechanic about replacing the whole unit. It seems that they are pretty cheap, and I can do it at home/ my friends shop. That being said, I'm wondering which part number will actually work, and if any additional programming is necessary.

    Alright, so right now I see some on Ebay that are listed as part # G920047070. They are labeled to work with the 2003, but I do not want to go through the trouble of installing one that will not work.

    You guys saved me a lot of trouble and I appreciate it. I will never go to a dealership again, unless I am forced to.

    Any advice on model numbers/installation?
     
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I suggest you use a part number which is the same or higher than the original inverter part number.
     
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  9. wafflefries1

    wafflefries1 New Member

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    I'm having the issue of finding one that is my model that is affordable. The mechanic labelled it as the G920047071, and I am only able to find the G920047070.

    Is it just a bad idea to install that one? I can see the potential issues.
     
  10. wafflefries1

    wafflefries1 New Member

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    My diagnostic was:

    P3125 - converter/inverter assembly
    Info codes 289, 292, 294
     
  11. ronlewis

    ronlewis Active Member

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    Patrick and some others here are experts, I'm not; but, it occurs to me that you might want to figure out why the inverter failed. I don't think they fail that often for no reason. The most likely cause is the coolant pump, or a coolant leak that makes the inverter overheat.

    Look at the reservoir - top of the engine, center/left/rear. When you get it running again, confirm that coolant is circulating through the reservoir. Consider replacing the pump - your mileage is past where they usually fail - while you have the inverter off, it'll be easier then, although it's not way hard anytime. It's the little motor under the inverter, right behind the driver's headlight.
     
  12. ChapmanF

    ChapmanF Senior Member

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    Hold the phone, it took two tries, over 3 days (in two separate weeks) to get you an answer. It seems premature to call it the right one.

    In post #4, you had P3000. That code gets reported by the HV ECU, but only when it has received a problem report from the Battery ECU. It means to go get the specific codes from the Battery ECU to find out what's going on back there.

    The Battery ECU is responsible for the battery. It has no responsibility for the inverter, and there are no codes you would get from the Battery ECU that would mean the inverter is at fault ... with one possible exception.

    The one exception would be the P3009 code, which indicates insulation leakage somewhere in the high voltage system. The inverter is one (out of eleven possible areas) where that could be happening.

    So, are they saying the read the code, and it was P3009, and they followed up by doing the workup on pages DI-331 to DI-338 of the manual to find out which of the eleven areas was the source of the leak, and that was how they concluded it's the inverter? The first post didn't make it sound like they had done that much work. (The workup process involves megger testers and taking trim and covers off stuff.)

    (page numbers from my 2001 manual, may differ in 2003.)
     
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  13. wafflefries1

    wafflefries1 New Member

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    I should have been more through, but I didn't want to complain too much.

    Long story short, the first time I called them up they lied to me. They didn't write down the diagnostic quote, and on top of that they didn't even know what was going on. So I called up 3 times total to double check that it was indeed the p3000. I talked to the chick that handled the whole thing, and she assured me that if I changed out the ECU, all would be good.

    I'll be honest, I don't know anything at all about vehicles, but I'm experienced in tech so I thought it would be easy to replace.

    That being said, it was just a lie to cover the fact that she didn't write it down, and didn't even know what she actually quoted me for.

    So after seeing the responses here I showed up asking a bunch of questions and made them run the diagnostic two more times. On the first day, they had me drive it around until it broke down in the lot which took me about 15 minutes. The reason they did this is because there was only a reading for the inverter, not the p3000, so he figured the other mechanic had cleared the codes. By the time I pulled back to the front they had let the techs go home, which I was pretty angry about, considering it was 4:45.

    Anyway, the diagnostic they had me drive around for (to get the triangle of death) never showed up after I did break it down. But the first OBD reading showed that there was an inverter issue, the ones I listed, so the mechanic concluded that was actually the problem. He finally contacted the original guy who had worked on it, and that was indeed what I was quoted for before this fiasco.

    Hilariously the chick who caused this whole thing "accidentally" misquoted me by $745. From $4745 to $4000 flat. Not that I would ever shell out that kind of dough, but it added fuel to my rage.

    I'm reasonably sure this is correct. The only other error codes were some engine misfires, that the tech said could be caused by just idling, and petty things.
     
  14. ronlewis

    ronlewis Active Member

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    I wouldn't believe anything those people said.
     
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  15. wafflefries1

    wafflefries1 New Member

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    My vehicle is in a city about 30 minutes away at the dealership. I can't have it towed currently, as AAA dropped me for too many calls last week lmao.

    That being said, I checked the reservoir when it first ran out, and it was a bit low. It was indeed bubbling at the top, so I'm guessing that the circulation was working.

    Given those additional codes, which indicate 3 separate sensor issues, could it be assumed that the pump would be the issue? I'd much rather shell out for that than the entire inverter module. I'll hunt around for some info.
     
  16. ronlewis

    ronlewis Active Member

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    No one here can help much without the actual codes. Again, not an expert, but I bet there can be multiple codes that suggest something about the inverter. If you find out the codes, I'll send you the diagnostic procedures from the manual.
     
  17. wafflefries1

    wafflefries1 New Member

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    Posted above.

    My diagnostic was:

    P3125 - converter/inverter assembly
    Info codes 289, 292, 294
     
  18. Patrick Wong

    Patrick Wong DIY Enthusiast

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    These codes mean that there is a problem with a current sensor within the inverter and it is reasonable to replace it.

    If you can only source a used G9200-47070 inverter at a reasonable cost, then try it and see what happens. If it doesn't work then tow your car to the local salvage yard and walk away.

    Good luck.
     
  19. ronlewis

    ronlewis Active Member

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    I'm probably going to have a spare one from my parts car. Not sure if it's good or how to tell if it's good, or how much work it is to take off, or how much costs to ship from Houston to AZ, but, lol, you'd be welcome to it.
     
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  20. wafflefries1

    wafflefries1 New Member

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    I'd be very interested if it's the correct model. It's not too bad to remove, probably a 30 min job fro what I've been told. Shipping would be around $100 from what I've gathered.

    Playing that Ebay waiting game right now, lmao. Two sold this month though, so I should be able to get one in the coming weeks.