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Battery Energy Control Module

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by TomLaNa, Mar 12, 2021.

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  1. TomLaNa

    TomLaNa Junior Member

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    OK, I'll pull that harness and check the resistance. Good source for that harness?
     
    #21 TomLaNa, Mar 15, 2021
  2. SFO

    SFO Senior Member

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    Looks like most of your local dealers are asking around 56 usd : Select a Dealer | Toyota - Call first to confirm pricing and availability, then head over to the Tyler toyota parts counter for instant gratification. Unlikely if it can be sourced for less elsewhere.
     
    #22 SFO, Mar 15, 2021
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  3. TomLaNa

    TomLaNa Junior Member

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    Thanks, I'll call the local dealer and see if they have one in stock.
     
    #23 TomLaNa, Mar 15, 2021
  4. dolj

    dolj Senior Member

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    I'd wait to hear from @TMR-JWAP. If no one has touched the battery since Toyota installed it, then I hate to think they got it wrong, but it is not beyond the realm of possibility.
     
    #24 dolj, Mar 15, 2021
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    The stains circled below are going to be a problem, if not already a problem. You have very obvious electrolyte leakage from a module, and possibly from 2 different modules. Sometimes this is caused by a small crack where the metallic insert is pressed into the plastic case. This usually leads to a P0AA6 HV isolation fault. It would be interesting to see what voltage reading you get if you connect all the busbars as they should be, install the safety disconnect and take a voltage reading between the metal case and each of the relay studs (on the battery side of the relays). I've seen some as high as 70 volts. This alone prevented the car from being able to go Ready.


    Leakage stain.jpg
     
    #25 TMR-JWAP, Mar 15, 2021
  6. dolj

    dolj Senior Member

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    @TMR-JWAP, did you get a chance to review the image in post #9. Is that bracket on the right way up?
     
    #26 dolj, Mar 15, 2021
  7. SFO

    SFO Senior Member

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    If the dealer installed this new OEM battery over 3 years ago, there will no longer be a warranty.

    Maybe the FIXD App/device isn't fully compatible with a toyota hybrid, and some DTCs (OBD2 codes) are being left off the table.

    After rescanning and confirming the known OBD2 codes (DTCs), try disconnecting the 12v battery for a couple of mins, then reconnect and attempt to start the vehicle (make Ready).

    If it starts (let it run for a couple of mins), then turn it off, and then doesn't start a 2nd time, you likely have a HV isolation fault.
     
    #27 SFO, Mar 16, 2021
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  8. TomLaNa

    TomLaNa Junior Member

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    Yes, the dealer only gave us a 30 day warranty on that battery and I questioned this at the time. The original battery had a 100,000 mile warranty and only 30 days on the new replacement battery.

    According to their website, the FIXD device is compatible :Compatibility | FIXD Automotive I did check the codes again and it's only showing the Control Module fault code.

    I couldn't work on the car yesterday and probably not today but I will disconnect the battery and see what happens.
     
    #28 TomLaNa, Mar 17, 2021
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  9. TomLaNa

    TomLaNa Junior Member

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    Well, no good on the battery reboot. The start button is a tan color instead of green and a small yellow triangle appears, then disappears on the information screen.
     
    #29 TomLaNa, Mar 17, 2021
  10. SFO

    SFO Senior Member

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    If that was a new OEM and installed at a toyota dealer, then it should be a full 3 year warranty. You might talk to corporate.
    After reconnecting the 12v source it will take two (2) power cycles to make the vehicle ready. Try starting the vehicle a second time.
     
    #30 SFO, Mar 17, 2021
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  11. TomLaNa

    TomLaNa Junior Member

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    No good on the two cycles.

    In the meantime I ordered a used computer and a wiring harness which will get here sometime next week. Would the computer have something to do with getting the car started on the engine or did something else develop?
     
    #31 TomLaNa, Mar 28, 2021
  12. mr_guy_mann

    mr_guy_mann Senior Member

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    Yes, the car uses the high voltage battery and one of the electric motors in the transmission to start the engine. So if there's a problem with the battery or its computer then nothing will function.

    Posted via the PriusChat mobile app.
     
    #32 mr_guy_mann, Mar 28, 2021
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  13. SFO

    SFO Senior Member

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    What OBD2 codes (DTCs) are you retrieving now?

    When was the last time the vehicle started (weeks, months), and was that before or after the last dealer visit?
     
    #33 SFO, Mar 28, 2021
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  14. TomLaNa

    TomLaNa Junior Member

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    I am still using the same code reader, so nothing has changed but I should get the one you recommended.

    It has been about three-four weeks since the car last ran and it was OK when it did run,a little bit rough from cold but then it was OK. I hadn't started the car in about 3 or 4 days after that run, then the battery went dead and it never started again with various fully charged batteries.
     
    #34 TomLaNa, Mar 28, 2021
  15. TomLaNa

    TomLaNa Junior Member

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    So in theory, once I plug in the hopefully good computer the car should start if the hybrid battery is OK. If not, then I guess it's time to buy a new battery or start changing out cells which I'm reluctant to do as it sounds like a temporary fix.
     
    #35 TomLaNa, Mar 28, 2021
  16. SFO

    SFO Senior Member

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    Given the current no start situation, there are no OBD2 codes (DTCs) being offered when using your current OBD2 scanner?
     
    #36 SFO, Mar 28, 2021
  17. TomLaNa

    TomLaNa Junior Member

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    Nope, ran it again and just the P3030 code.
     
    #37 TomLaNa, Mar 28, 2021
  18. TomLaNa

    TomLaNa Junior Member

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    I downloaded the Mr.Prius app but it won't communicate with the FIXD reader, so I will have to purchase one of the approved readers.
     
    #38 TomLaNa, Mar 29, 2021
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  19. TomLaNa

    TomLaNa Junior Member

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    I received the new/used hybrid battery computer and the new wiring harness today. After installing the computer and clearing the error codes with the Dr.Prius app the car started and I used it for about 15 miles. When I got the car home I charged up the battery as per the Dr. Prius app and it's charged to 70% and I assume that this can be done every day until it levels out.

    I am waiting for a new torque wrench as I don't have one that can tighten the nuts to such a small level and will install the new wiring harness as it seems prudent to change it considering the corrosion on the previous computer plug, then I will remove and clean up the nuts on the rear bank of nuts.

    Pack Voltage: 226.57
    Discharging: 0.06
    State of Charge: 70.05%
    Blade Voltage: 8.09
    Voltage Diff: 0.20v
    Max Charge: 7.37hp

    Thanks
     
    #39 TomLaNa, Apr 1, 2021
    Last edited: Apr 1, 2021
  20. TomLaNa

    TomLaNa Junior Member

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    I have run the diagnostics from the Dr.Prius app and the battery pack has 82.15% capacity left. My question is, should I purchase the Prolong hybrid battery charger to maintain the battery or should I also add the battery discharger? There are currently no error codes related to the hybrid battery.
     
    #40 TomLaNa, Apr 3, 2021
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