Code still remains AFTER replacing bad module?? Help!

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Levi Gonzalez, Sep 22, 2021.

  1. Levi Gonzalez

    Levi Gonzalez Junior Member

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    Got the P0a80 code on my 140k / 2013 prius. (This Prius had a refurbished battery installed @106k)

    Got the Dr Prius app and it showed block #12 was bad.

    Opened it up replaced block #12 (bought 2 refurb cells), clean the buss bars with a nylon brush and applied some deoxit. Made sure everything was perfect.

    Popped it back in and still getting the codes (torque pro AND Dr Prius are throwing the P0a80).

    And it's still showing the Same block (#12). it's a differential of up to 0.85v sometimes.
    _____________________________________

    What's going on here? Is it a bus bar / Connector issue? Computer issue?

    Should I open it up one more time and swap #12 modules with another block, and see if #12 still is showing an error?
     
  2. Levi Gonzalez

    Levi Gonzalez Junior Member

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    Update: Opened the battery again and swapped #11 (which has never had problems) with #12, and STILL #12 is giving problems on the app (albeit not as often as before).

    When the peak voltage of the battery pack goes high (240v or so) #12 will go 0.8v high the 2 seconds later go 0.5v low.

    Does this sound like a computer issue?
     
  3. sam spade 2

    sam spade 2 Senior Member

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    The Deoxit goes on AFTER the connection is tightened.......not before and not on the conducting surfaces.
     
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  4. Grit

    Grit Senior Member

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    Wack o mole stage 1 completed.
     
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  5. ChapmanF

    ChapmanF Senior Member

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    CAIG makes a bunch of DeoxIT products, several of them straight contact cleaners, and a few of them greases. The cleaners come in 5% and 100% formulations. The OP hasn't said which product was used.

    It won't surprise anyone that the straight contact cleaners are used right on the conducting surfaces before mating them. CAIG says "more is not better" and recommends that if a 100% formulation is applied, it is wiped off before use, which will leave a thin film. The 5% solution can just be applied and left there, and will be a thin film after the solvent evaporates.

    Their greases, while it might be more surprising, are also specified for direct application on the conducting surfaces.

    Technical-Information - CAIG
     
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  6. BiomedO1

    BiomedO1 Member

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    Trust in the ALL MIGHTY COMPUTER, it is never wrong - until it is. You need to individually load and voltage test each cell. The computer is only giving you a guess as to which cell or cells are bad. It could be a few cells north or south of #12. The only way to know for sure is to test them individually. Pay particular attention to the bookend cells of each bank; in my experience one of them is usually bad.

    Re: DeoxIT products, used them for over 30 years. Works GREAT, as long as your applying them properly - per instructions.
     
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  7. Soluzon

    Soluzon New Member

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    The computer stores permanent error codes and they stay until you've driven a normal driving cycle (per Toyota) with the problem fixed, then the computer clears it. That it's still showing block 12 may mean you are seeing the permanent code and need to drive it some more before it clears.
     
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  8. ChapmanF

    ChapmanF Senior Member

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    Well, it's guessing based on 14 little copper wires leading directly to 14 pairs of modules.

    A pretty good way to 'guess'.
     
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  9. BiomedO1

    BiomedO1 Member

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    Well I really don't want to argue this point.

    The fact is that he's taken the pack apart twice. We can either all laugh at him and let him "bang his head against the wall"; or we can try to help him out. Even if he's going after the correct set of cells, properly testing the individual cells will give him a definitive answer and hopefully prevent a fourth or fifth tear-down. No offense Levi...

    good luck...
     
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  10. ChapmanF

    ChapmanF Senior Member

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    One thing that could be fun to try would be to open the case up again, leave all the modules where they are, and swap the block 12 sense wire with one of the other sense wires (whichever one is shorter might need you to kludge up a little extension, and insulate your joint really well). Then see what block the ECU is complaining about. :)
     
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  11. Levi Gonzalez

    Levi Gonzalez Junior Member

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    update: I tried stock oxidized bus bars. then grease. then sanded the bus bars and polished them till they look like a shiney penny...made zero difference
     
  12. Levi Gonzalez

    Levi Gonzalez Junior Member

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    how much longer? I put probably 200 miles on it since I out the new cells in
     
  13. Levi Gonzalez

    Levi Gonzalez Junior Member

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    thanks for the information. can you either tell me or post a link of somewhere I can see how to individually load and test cells?

    and what does "bookend cells of each Bank" mean?
     
  14. Levi Gonzalez

    Levi Gonzalez Junior Member

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    It's either got to be the wiring harness or the computer. Because...

    Several sets of modules were tried in #12 and for the most part, made No Difference.

    So the odds of several (good) modules All becoming faulting when they're inserted in block #12? idk about that.

    What's a more viable option is that the computer or wiring harness is signaling a false code to #12 OR that it's not block #12 at all,rather a block nearby #12.

    Correct me if I'm wrong, but doesn't this seem logical?
     
  15. Soluzon

    Soluzon New Member

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  16. BiomedO1

    BiomedO1 Member

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    Sorry Levi, I'm mainly in the Prius plug-in forums. Try this link:


    I think those batteries are 7.4 VDC nominal. Assuming 80% capacity, they shouldn't go below 5.9 VDC when you apply the load. I usually don't get hung-up on specifics, a bad battery will go down to a couple of volts or zero as so as you apply the load. A good battery should remain in the 6 volt battery "yellow" weak zone for a good 5 seconds.
    Don't lean on that load button too long, 3-5 seconds on each battery should tell you if it's good. That tester will get hot going through all those batteries; but hopefully you'll get all those bad cells.

    Most people only look at battery voltage and think it's all good - but if a battery won't carry a load, it can't do it's job.
     
  17. BiomedO1

    BiomedO1 Member

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    Correction:
     
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