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Battery Pack #2 -16V and #3 is +24V...WTH, help please

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Trevor Pickens, Mar 5, 2023.

  1. Trevor Pickens

    Trevor Pickens New Member

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    I cannot find anything on the internet about this wide variation in voltage in #2 and #3.

    As you can see on the detailed list that there is a wide variation in #2 and #3. That's obviously not normal. The code kicked to me was P3000 without any detail (other than 123). There is a P0420 code, and C1241 (low or high voltage). These seem to be downstream problems, no?

    Also look at the the polarization from #1 and #2. They are exactly opposite in their output. Can someone explain?

    When I reset the codes by disconnecting the negative 12v terminal the car will ride seemingly endlessly with the CE light on but not red triangle. When I reset the codes in Techstream the CE and red triangle both come back on within 5 miles.

    Can anyone shed light here?

    Should I replace packs #2 and #3?

    Should I check connectors, corrosion, or perhaps superficial damage?
     

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    #1 Trevor Pickens, Mar 5, 2023
    Last edited: Mar 5, 2023
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!
    Yes. Check the spades/tiny wiring on the voltage sense harness, including the end connector/socket, and HV battery ECU that it plugs into.

    FYI : you're moderated until you've posted 5 times.
     
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  3. PriusCamper

    PriusCamper Senior Member

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    Open up your ECU and I bet you'll find a build up of corrosion on the voltage sensor pins that's creating micro-shorts, which creates those weird voltage readings. It's one of the most common failure points on Gen2 battery packs.
     
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  4. Trevor Pickens

    Trevor Pickens New Member

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    ----------------------------------------------------------------------------------

    Thank you for the welcoming message; I appreciate it.

    Is this the HV Battery ECU? (Photo attached with arrow)

    Also, in the second image you can see I have the P0A0D code which I've been told is an improperly installed service safety plug. PErhaps I damaged it by handling it too roughly or something. I'm not sure. I'll have to look in there and check.

    I'm learning so much here. Thanks for the help.
     

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  5. SFO

    SFO Senior Member

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    Yes. If needed, you can purchase a new voltage sense cable from a dealer for around 60+.

    How many miles on the vehicle, and is the HV battery still the original?
     
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  6. Trevor Pickens

    Trevor Pickens New Member

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    I believe it's still the original. I just bought the vehicle 6 weeks ago.

    I checked the connector as you mentioned and yes there was the corrosion. Stupidly I tried cleaning it with a wire brush and my car is a dead duck now tripping a p3030 code.

    Also does this look like the correct connector piece? The eBay seller says it's for 2007 Prius which is my model but I just want to double check.

    Thank you Screenshot_20230308-074508.png IMG_20230308_063805224.jpg
     
  7. SFO

    SFO Senior Member

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    The part# you want is 82165-47040, don't install a used harness (unless free). Here are some online dealers with pricing, call your local dealership(s) and see if they will price match, or just have it delivered. Unlikely if you will find a NEW harness on ebay for less.

    https://parts.springhilltoyota.com/p/63467258/82165-47040.html

    https://parts.valdostatoyota.com/p/63467258/82165-47040.html

    https://parts.reinhardtmotors.com/p/63467258/82165-47040.html

    If that is a picture of your existing connector, then you have some ECU pins stuck inside (green bits) and you will need to source a used ECU as well. Tampa Hybrids should have one, or AutoBeYours could also. Some members here will also be able to help.
     
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  8. Trevor Pickens

    Trevor Pickens New Member

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    Are you talking about the male piece that the connector plugs into? All of those pins are intact. I have a picture I'll pot but I'll need to post a better quality one later on. But do you think the corrosion could leak into the ECU? Given that the pins are all on the male piece of the ECU I should be able to replace the connector piece and the P3030 stop showing, no? Also the problem may be deeper than just the corrosion, right? It may be some bad battery packs causing such a wide sing in voltage. Just curious. Thanks again.

    Sorry for the poor quality image. Again, I'll post a better quality one after work. IMG_20230308_063826807.jpg
     
  9. dolj

    dolj Senior Member

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    Yes, it is but it is just called the battery ECU. And the big battery, even though it has high voltage is called the hybrid vehicle battery.
     
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  10. SFO

    SFO Senior Member

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    Just to be clear :

    [​IMG]

    Is this the existing wire frame #2 (voltage sense cable) currently installed on your vehicle?

    Yes, and worse things have happened.
    Always best to follow the workup for any DTC reported. Here is the workup for DTC P3030 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/20zmw/cip3030b.pdf

    If the pins are fully intact, then this should be the case. The "connector piece" is known as part# 82165-47040, or were you planning to cut and splice?
    Unlikely, or you would have associated DTCs that point in that direction.
     
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  11. ChapmanF

    ChapmanF Senior Member

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    Little PSA: when you see things in the parts catalog with commas like this:

    PLUG, SPARK
    PUMP ASSY, ENGINE WATER
    RING, O
    VALVE ASSY, WATER W/BRACKET
    WIRE, FRAME, NO. 2

    those things are spark plugs, engine water pumps, O rings, water valve assemblies, and number two frame wires.

    There's a risk of looking a bit goofy if one goes around calling things plug sparks, pump waters, ring Os, valve assembly waters, and wire frames.
     
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  12. Trevor Pickens

    Trevor Pickens New Member

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    ------Thank you!------

    SFO you were correct about the pins being stuck in there, so I ordered not only the Wire frame 2 but also the battery ECU unit. It'll be here in a few days and I'll lyk how it goes.

    Interestingly, when I did a voltage check for each battery pack a few days ago they all read about 8.20 give or take a .02 or .03. One of them read 8.14. In your estimation would the bad connector piece have been the likely culprit for those high numbers?
     
  13. Trevor Pickens

    Trevor Pickens New Member

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    I noticed that when I took off wire frame #2 every battery pack, from one end of the pack to the other (+ and - on same pack) the voltage read correctly 7.6 or very close for every single one. However, when I checked the voltage on the #2 side (not the side with the safety switch/plug) and checked two packs combined all of them read 15.2 (or close to it) except for #19 and #20 (which of course is where the safety plug leads into). The first photo (which is on the #2 side) shows 4.26 volts when I connect the two packs. When I checked the voltage on the #1 side (safety plug side) the voltage read 3.76.

    This baffles me. Also when I check led the #1 side after the wire frame 2 was disconnected, I was looking for voltage by connect the + and - from different packs and found most of them were at 0 or close to them. Some even read -0.1.

    Can anyone explain?

    I appreciate it. IMG_20230312_101507075.jpg IMG_20230312_101923190.jpg IMG_20230312_101938597.jpg
     

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  14. ChapmanF

    ChapmanF Senior Member

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    If you have the #2 frame wire off, and the other side bus bars are still on, you should be able to see ~ 14.4 volts (from the frame wire side) across the pairs of modules that are connected by bus bars on the other side. You would not expect a meaningful reading between other pairs of terminals, and that includes also the ones your photos show, which are at the modules joined by the service plug (which is presumably removed, no?).
     
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  15. Trevor Pickens

    Trevor Pickens New Member

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    Thank you for that. I just noticed while installing the new wire frame #2 that the voltage for the whole battery is 219. I understand it should be about 7.2 per pack but mine is hovering around 7.6. Could this just have been a result of the bad battery ECU unit from before and perhaps it'll "work itself out" to the proper levels once I install and start driving the Prius after I install the new battery ECU?

    BTW you were correct. Once I plugged the safety plug in it read the way it was supposed to.

    Thanks
     
  16. ChapmanF

    ChapmanF Senior Member

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    You're still saying wire frame. You should probably try changing your plug sparks and bearing wheels. :)

    7.2 volts is "nominal" for a six-cell NiMH module—1.2 volts per cell.

    Real-life voltages will vary, from about 1 volt per cell at full discharge to maybe over 1.4 V/cell at high states of charge.
     
  17. Trevor Pickens

    Trevor Pickens New Member

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    Thank you everybody for your help. Once I replaced the wire frame #2 and the battery ECU everything (except the catalytic converter which is another thread for another day) works great. I appreciate the help.

    Just a word to the wise for anyone doing this themselves, you will need to take the back seats (top parts) out to have ease or access to the battery. Trust me. Do this it'll save you a lot of stress on your body.
     
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  18. douglasjre

    douglasjre Senior Member

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    Can you please provide:

    1 complete list of all codes
    2 prob invalid in info now that you clear codes routinely but pls tell me miles drive, startups since, and time since codes last cleared, if the data given reflect time since seller cleared codes and not time since you last disconnected battery/cleared codes
    3 name and contact info of person who scammed you into buying this car

    #2 above reflects how you should not be attempting these repairs AND how you should have paid for a prepurchase inspection at a dealership
     
  19. Tideland Prius

    Tideland Prius Moderator of the North
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    You could’ve just said the first two without implying he got scammed. What’s done is done and if you want to help the current problem, then do. If not, then don’t.
     
  20. douglasjre

    douglasjre Senior Member

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    Better to be honest about the problem. If he got scammed he may have recourse. Don't let more time go by. If you have the evidence that he scammed you take action while you can. Why sugarcoat it? Sugarcoating it prevents you from addressing it. If you have the evidence that he cleared codes to scam you then you'd better do something about it now while you can if you can.

    Political correctness or deliberate positivity while avoiding discussing the negatives prevents us from fixing issues.
     
    #20 douglasjre, Apr 11, 2023
    Last edited: Apr 11, 2023