Car won't start, P3108-594, UO129-220/528, UO146-435

Discussion in 'Gen 2 Prius Main Forum' started by Kris_Parker, Jan 10, 2024.

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  1. Kris_Parker

    Kris_Parker Member

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    Good evening guys! I got 2006 Prius with following codes: P3108-594, UO129-220/528, UO146-435.

    The car itself won't start and all I hear is one click instead of usual 3. Dashboard, A/C, Steering wheel, Radio, nothing will work or turn on (the dashboard does show the check engine light, so it does work, but there is nothing expect the open door and engine light). After some reading I checked all the fuses (all good), I also did disconnect/connect 12v battery + HV battery safety plug and the car have worked for a couple of hours before it just stopped. At this moment I suspect either the Hybrid Vehicle Control Ecu or the Wires, probably tomorrow I will check all the wires for resistance, and if they are good I wanted to try and replace the Hybrid Vehicle Control Ecu.

    P3108-594 = A/C Amplifier Communication Circuit Malfunction
    U0129-220 = Lost Communication With Brake System Control Module
    U0129-528 = Lost Communication With Brake System Control Module
    U0146-435 = Lost Communication With Gateway "A"


    Any ideas or advice on what to do? Maybe someone had the same problem before.
     
    #1 Kris_Parker, Jan 10, 2024
  2. PriusCamper

    PriusCamper Senior Member

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    It makes sense that the lack of clicks means a relay isn't firing up that turns on that ECU, but as far as I know those missing clicks are coming from your hybrid pack, not the dash... As in not the bad ECU you're looking for. ---> Also, get your 12v charged up to 100% and check your fuses.
     
    #2 PriusCamper, Jan 10, 2024
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  3. Kris_Parker

    Kris_Parker Member

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    It's better to check the Master Relay instead of replacing the ECU? I did checked all fuses and they're fine. I will try and replace the 12v but that's probably not the problem.
     
    #3 Kris_Parker, Jan 10, 2024
  4. PriusCamper

    PriusCamper Senior Member

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    Low voltage on a 12v does weird things... I've never heard of a master relay in Toyota Hybrids, only Honda Hybrids. Check engine light has error codes to assist you. But in general, lost communication with an ECU isn't a mechanical problem, but a fried or bad connection. And since its only pointing towards brake ECU there's something missing that we need to find in this diagnosis. Maybe @ChapmanF will chime in, he usually has a good sense of the cause of these kinds of glitches.
     
    #4 PriusCamper, Jan 10, 2024
  5. Kris_Parker

    Kris_Parker Member

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    Sorry for confusion, by master relay I meant the Main Relay, the one we have in our hybrid pack. I do have pictures from Techstream but the website will not allow me to post any of them. It is not a mechanical issue, so that's why I've checked all the fuses, and wanted to check resistance on Hybrid Vehicle Control ECU Wires because that's what manual says. Maybe I have to check an Inverter and the wires connected to the Inverter because it may be where the problem comes from. I suppose, I have to play whack a mole until I will find some loose connection or a corroded wire.
     
    #5 Kris_Parker, Jan 10, 2024
  6. ChapmanF

    ChapmanF Senior Member

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    It's the HV control ECU that decides when to click the system main relays and power up the car, and only after its checklist says ok to do so. So in most cases where you're not getting those clicks or power, you don't go replacing the relays or replacing the ECU, you just ask the ECU why it is deciding not to click the relays.

    U codes are network communication issues. There are a dozen ECUs in the car and they communicate on networks, and things will be funky if they can't. The sections in the repair manual on "multiplex communication" and "CAN communication system" are too detailed to put much useful summary info here; better to just go straight to the source and dig in.

    Toyota Service Information and Where To Find It | PriusChat
     
    #6 ChapmanF, Jan 10, 2024
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  7. Kris_Parker

    Kris_Parker Member

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    Thank you for the answer! If you can spare a minute to look at this file, page 21 and 26. That's were they say to check the branch wire, battery and body ground wires, and if they're okay, then you have to replace the Hybrid Vehicle Control ECU. I may got a little bit confused on how I'm suppose to use the manual and that's why I'm doing this in a wrong way.
     
    #7 Kris_Parker, Jan 10, 2024
  8. ChapmanF

    ChapmanF Senior Member

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    The DTC Combination Table on page CA-21 is indicating that with the U0129, you should investigate "skid control ECU communication stop mode", and for both the U0146 and P3108, you should investigate "gateway ECU communication stop mode". Those start on page CA-27 and CA-32, respectively.

    But don't overlook the NOTE at the bottom of page CA-21, saying that if you have U0146 or P3108 (you've got both), you should check as instructed on page MP-7 in the Multiplex Communication System section, before proceeding to the gateway ECU communication stop checks.
     
    #8 ChapmanF, Jan 10, 2024
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  9. PriusCamper

    PriusCamper Senior Member

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    Soon as forum software is upgraded to newest version photo problem will be fixed. You can try cut and paste, that sometimes works. Or turn off Java script in your browser, or post photos elsewhere and post a link here.

    Did you have any symptoms or anything odd happen leading up to this problem?
     
    #9 PriusCamper, Jan 10, 2024
  10. Kris_Parker

    Kris_Parker Member

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    Okay, I will keep that in mind.

    I did had a little accidents to the driver side, but I was driving for a whole week with no problems. Not so sure if this is the problem or not.
     
    #10 Kris_Parker, Jan 11, 2024
  11. Kris_Parker

    Kris_Parker Member

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    Problem solved: (I hope)

    The problem laid in a fuse box under the hood, I don't know the exact name but it wasn't the relay or fuse itself, but the big "fuse" on a left side. Here is a video, after fixing this, the car started to work and that's was all. Took us hours to figure out why the car didn't get the positive, and where is the problem, but then we did checked this "fuse" and he was broken. Not sure of the cause, but I think this may happened because of how I jumped started the car when my battery got discharged. Probably because of that, this "fuse" blown up. Thanks for the help!
     
    #11 Kris_Parker, Jan 11, 2024
  12. ChapmanF

    ChapmanF Senior Member

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    How did you fix it?
     
    #12 ChapmanF, Jan 11, 2024
  13. Kris_Parker

    Kris_Parker Member

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    I did the same what the guys on a video did. In other word I just soldered it.
     
    #13 Kris_Parker, Jan 12, 2024
  14. ChapmanF

    ChapmanF Senior Member

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    Sounded like you might have done that. This post shows how to replace the fusible link with a new one that you can trust to protect at the right current levels in case of another overcurrent situation. Whether your soldered 'repair' will do so isn't dependable.
     
    #14 ChapmanF, Jan 12, 2024
  15. Kris_Parker

    Kris_Parker Member

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    You're absolutely right on that, and this 'repair' is just a temporary solution. I'll probably get a new fusible link and replace it.
     
    #15 Kris_Parker, Jan 12, 2024
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