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Do these bus bar connections look corroded enough to cause HV errors?

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by GreenTea&SaltWater, Dec 30, 2022.

  1. GreenTea&SaltWater

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    "Picture added in reply below"

    The "Check HV battery" error came up and I checked on Techstream and it's telling me multiple battery blocks are weak. I know these batteries are good cause I just replaced them from a reputable user on here. And it doesn't seem like a bad module issue I've had in the past where when I reset it the issue comes back in 50 miles but this time it's every 2-10 miles, and it's multiple blocks.

    I cleaned the corrosion twice in the previous 3 years and 20k miles with vinegar and salt, but why do they keep corroding so quickly?
     
  2. GreenTea&SaltWater

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    Ah damn I forgot to add the picture here it is
     

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  3. bisco

    bisco cookie crumbler

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    i would say yes, but that looks more like rust. any green on them?
     
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  4. Noahdoge

    Noahdoge Active Member

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    Hopefully you didn’t clean the nuts with vinegar and salt.
     
  5. ChapmanF

    ChapmanF Senior Member

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    The busbars mostly corrode where you can see it, and where you can see it is where it doesn't matter. With the nuts torqued correctly, the contacting surfaces (where it does matter, and you can't see it) are under enough pressure to stay gastight, and protected from corrosion. Those areas tend to still be shiny when revealed by removing the nuts and bars.

    If you've been playing whack-a-mole for a while, replacing an individual module or two now and then, it sounds like the rest of the pack hasn't been getting any younger, and you've just got more moles this time 'round.
     
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  6. GreenTea&SaltWater

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    I've replaced every module in the pack so the wacka mole game is over. But I found one of the modules was stripped and the nut wasn't tightened properly. Can I possibly remove that bolt and replace it with this other one that came off of another module I had by accident? Or am I going to have to replace the module?

    Also the corrosion in between the nuts and bus bars as well there is no clear spot.
     

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  7. GreenTea&SaltWater

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    And another thing, that stripped module is in battery block 8, so it wasn't even the one that was giving my battery issues which are blocks 9 and 10.
     
  8. mr_guy_mann

    mr_guy_mann Senior Member

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    Well, if you are adventurous and wearing protective gear, you can remove the module and grab the stud with vice grips and see if it will unscrew. Getting it to seal again might be a challenge.

    Me, I wouldn't as KOH is a potentially nasty electrolyte.

    If you are getting a P0A80 then the battery ecu is seeing too much voltage difference between blocks at some point during use. Assuming that the voltage sense wires and ecu connection are ok, then your battery modules are problem.

    Doesn't matter how many you replaced when- some have different capacities and/or state of charge than others.

    Posted via the PriusChat mobile app.
     
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  9. GreenTea&SaltWater

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    It's not a P0A80. I've had that in the past due to some bad battery modules. I scrubbed away the corrosion from the bus bars and also replaced that stripped module with another good one and 12.5 miles later it's running fine so it looks like the issue may be fixed.
     
  10. ChapmanF

    ChapmanF Senior Member

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    What's your price for telling us what the code was, then?
     
  11. TMR-JWAP

    TMR-JWAP Senior Member

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    I recognize the handwriting on those module stickers. :D If you need new fasteners, McMaster Carr has stainless available under item # 93033A106. They are almost exactly identical to the OEM, just very slightly smaller in flange diameter. A pack of 50 is currently less than $12.
    Very important to torque these fasteners correctly to 48 inch-pounds. (Equivalent to 4 ft-lbs). Some people/shops use 60 inch pounds, but the Toyota repair manual states 48. 60 is safe, but it's easy to go too far and damage the stud threads. There's no easy reliable repair for that, except replacing the module.
     
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  12. GreenTea&SaltWater

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    It was just 2 P0-something codes that said "battery block 9 and 10 become weak". I'll never know for certain which was the one causing the issue since the stripped module with the loose nut was on block 8, not 9 or 10. But they were all very corroded. Vinegar, salt, and baking soda and a wire brushed fixed the job. @TMR-JWAP

    Good to know i can just buy a new pack for $12 next time.
     
  13. GreenTea&SaltWater

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    There was no green on them this time. What do you think could be causing rust?
     
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  14. bisco

    bisco cookie crumbler

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    in LA? no idea. has the car ever spent time in a moist environment?
     
  15. TMR-JWAP

    TMR-JWAP Senior Member

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    I've seen the nuts get the zinc coating stripped off when using solutions for removing previous corrosion. Unfortunately, once the zinc is removed, the bare steel underneath can rapidly rust if exposed to moisture/high humidity.
     
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  16. GreenTea&SaltWater

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    Only other place and where I'm currently living is the Mojave Desert in SoCal so it doesn't get much dryer.
     
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  17. mr_guy_mann

    mr_guy_mann Senior Member

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    Those codes are typically "the same" as P0A80, just with higher threshold values. ie, a "minor" voltage difference for a certain amount of time will set a P0A80, but having a greater voltage difference (for longer?) sets P30xx, "battery block xx becomes weak". The exact criteria are "Toyota's intellectual property".

    If your repair works, then great. Experience of many forum members seems to indicate that it most often doesn't.

    Posted via the PriusChat mobile app.
     
  18. GreenTea&SaltWater

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    My repair is holding up. It was definitely the rust and the stripped loose nut on battery block 8 that was causing the issue. I've repaired my battery many times I'm pretty much an expert at it. I'm using a hacked version of Techstream btw
     
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