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My 2nd P0AA6-526 Hybrid Battery System Isolation Fault on Original Battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Lighthouse-Beacon, Nov 3, 2020.

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  1. Lighthouse-Beacon

    Lighthouse-Beacon Member

    Joined:
    Oct 24, 2018
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    Location:
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    Vehicle:
    2009 Prius
    Model:
    Two
    This is my second Hybrid Battery Voltage System Isolation Fault for this original battery pack on a 2009 Toyota Prius with 233k miles. It's a little different this time as I am not throwing a 612 subcode yet, just seeing the vehicle insolation resistance reduction cod. I did what I did last time, that thread is here:
    Help With Next Move: Code P0AA6 and Subcode 612 | PriusChat

    A good graph to have for identifying the subcode locations is:
    sEGF0zE.jpg

    I did the test again to see if it was in the HV Battery Box (Most likely a leaky module like last time) That process is here:



    <iframe width="560" height="315" src="Gen 2 Prius P0AA6 battery leak confirmation - YouTube" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

    thumbnail_IMG_1905-cleaned.jpg

    The test did not confirm the leak was in the HV Battery area as I show 0.00V, which could mean one of the grounding modules is at the safety plug connection, if that's the case this test won't work. I've made it about 12 months since replacing a pair of modules, and 8 months prior to that before replacing a pair of modules.

    I am going to keep driving it and see if the ECU reports a bad mod soon. That's what I did last time. I took a lot of grief for installing this switch to reset the car and keeping driving with. But I am using it in the morning to get to work and I am glad I did. That thread is here:
    Installed a Switch to Keep Driving :) | PriusChat

    I am going to keep driving and watch for more detail codes then decide to 'wack a mole' a few mods or just buy the replacement pack here:
    New Prius Battery Kit (GEN2, 2004-2009) - New Prius Batteries LLC

    Which I would have done already had I not been 230K+ miles.
     
    #1 Lighthouse-Beacon, Nov 3, 2020
    tangerino likes this.
  2. yups

    yups Junior Member

    Joined:
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    Vehicle:
    2006 Prius
    Model:
    II
    Thx for posting diagram. My P0AA6-526 turned out to be fan motor. It evened affected abs codes...
     
    #2 yups, Sep 16, 2023
  3. Eduardo Taylor

    Eduardo Taylor Junior Member

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    Location:
    Locust Grove, GA
    Vehicle:
    2009 Prius
    Model:
    Base
    Hey there can you explain a bit more on that situation? I am experiencing the same issue and I pulled a P0AA6-526 code and looking to get answers
     
    #3 Eduardo Taylor, Oct 23, 2024 at 1:46 PM
  4. ChapmanF

    ChapmanF Senior Member

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    Vehicle:
    2010 Prius
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    IV
    It won't have been the fan motor; the P0AA6 code is exclusively about isolation failures in the high-voltage system, and there are not any fan motors in the Prius than run on anything but 12 volts. But it happens surprisingly often that someone can have a code for one reason and have the problem go away, or seem to go away, while they're looking at something else, and then conclusions get drawn.

    There's a useful graphic posted up in #1 above, but the color highlighting is wrong. Here's the fixed version:

    [​IMG]

    The INF code 526 that you have is just the one that sets first, and does not tell you any specific area of the car where the isolation fault should be found. For that, you need a 611, 612, 613, or 614 code to come up.

    The specific code will come up on your next power-up of the car, as long as you do not clear the P0AA6-526. Powering up, the car will say to itself "hmm, I see a P0AA6-526 from last time, I will watch for the fault while powering up this time, and set the specific code for the area where the fault is."

    If you do clear the P0AA6-526, it'll just come back the next time the fault is detected, and you'll be in a useless cycle of clearing and getting P0AA6-526 and never getting a more specific code.
     
    #4 ChapmanF, Oct 23, 2024 at 2:00 PM
    Brian1954 likes this.
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