Dreaded P0A080 Code - Car Running / Charging Good.

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by PriuSocal, Jan 25, 2026 at 5:00 PM.

  1. PriuSocal

    PriuSocal Member

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    So after getting this car last week, I was driving today and coming to a light the “Check Hybrid System” came on along with the TOD, VSA and CEL lights. I have an Autel AP200 dongle specifically for Toyota and when looking up the HV battery / block voltage values, all 14 were very similar hovering around 16 and 17v. It also had a 0 under “times battery very low” or “very high”.

    I am new to reading HV battery readings and as mentioned above, bought an AP200 (recommended by another user to buy) and have Dr. Prius app installed on my ipad. I have looked up a few other threads on here about this very common code but symptoms all appear to fluctuate. The weird thing is the car is running good, charging and holding a charge in what appears to be normal fashion. I thought to check the hybrid fan 1st but I am in unfamiliar territory with the HV batteries and will need to rely on other posts and youtube videos for now.

    A little on the car:
    - 2015
    - 260k
    - 12v Battery Replaced right before i bought it
    - HV battery original or replacement or service unknown
    - History showed P0300,P0302, P0303 and P0304 codes when I ran a check but CEL off and monitors incomplete (most likely due to the battery replacement).
    - Car had a Multi Point Inspection at Toyota prior to sale and NO mention of failing or HV battery or current issues/codes, only random things like brakes and struts etc.
    - The History codes are now gone and only P0A80 is now current code.

    Lastly, I apparently saved a PDF copy of the live data for the HV battery on the Autel App but cannot figure out how to access the file as it is not under my downloads or anywhere when searching and the app wont show a saved pdf file folder.

    I appreciate all the help or direction.
     
    #1 PriuSocal, Jan 25, 2026 at 5:00 PM
  2. PriusCamper

    PriusCamper Senior Member

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    Used car dealers have a reputation for selling vehicles that they can barely keep that error code from coming back long enough to sell it...

    I suspect you have a weak cell in your pack that runs ok until there's a high amp load going through it during hard acceleration or hard braking. To confirm you can monitor "volt diff" numbers via Dr. Prius app while driving and you'll notice that number going up during high amp loads. As long as battery temps don't go too far above 120ish you can keep driving and clear code as you go.

    As for what to do next, I'd suggest studying Lemon laws in your state and holding the seller's feet to the fire for a rebuilt or brand new replacement battery pack.

    You could also buy a used replacement module for $40 and put it in and if you're luck get a year out of it... Or you could buy some gear and do a thorough rebuild yourself.
     
    #2 PriusCamper, Jan 25, 2026 at 5:11 PM
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  3. Brian1954

    Brian1954 Senior Member

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    Look at the freeze frame data for the P0A80 code. That data will show the voltages of the 14 battery blocks when the code was triggered. One of those 14 battery blocks will show a voltage lower than the other 13 blocks. Then, you need to decide if you want to replace battery modules to fix the problem or replace the complete hybrid battery.
     
    #3 Brian1954, Jan 25, 2026 at 5:16 PM
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  4. PriuSocal

    PriuSocal Member

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    I bought it from a private party. So, usually those sales are AS-IS sales here in CA unless stated otherwise. I have been reviewing some videos and looks like the testing for the HV batteries is extensive using apps like dr. prius etc.
     
    #4 PriuSocal, Jan 25, 2026 at 5:18 PM
  5. PriuSocal

    PriuSocal Member

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    I will do that next and report
     
    #5 PriuSocal, Jan 25, 2026 at 5:19 PM
  6. PriusCamper

    PriusCamper Senior Member

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    The Dr. Prius app testing won't help find the bad cell/module that needs to be replaced. But if you want to pull the pack for testing we can walk you through that.

    More to the point, what's your budget for resolving this? Because upgrading to brand new sodium-ion would be a significant upgrade to the performance of your car for years to come. Way more fun to drive than even a brand new OEM pack.
     
    #6 PriusCamper, Jan 25, 2026 at 5:25 PM
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  7. PriuSocal

    PriuSocal Member

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    At this point I dont have a significant budget towards battery replacement. If determined that it needs a new battery, I would need to hold off on it for a few months if that.

    I recall when my transmission went out on my gen 2, after replacing it and fixing it. The P0A80 came on as well but I was not having issues with the battery. After resetting codes, it did not come back on and it's been 5-6k miles since. So this is the reason why I dont jump directly to assuming my battery is bad until I do a bit more research.

    Also, never used the Dr. Prius app but can I use my AP200 as a VCI for the app or do I need something else to connect it from my ipad to car.
     
    #7 PriuSocal, Jan 25, 2026 at 5:43 PM
    Last edited: Jan 25, 2026 at 5:57 PM
  8. rjparker

    rjparker Tu Humilde Sirviente

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    A multipoint inspection is almost always done by the oil change guys whose marching orders are to sell brakes and struts.

    The Dr Prius guys will tell you their apps testing won't be accurate with a current P0A80 and clearing it does not solve the problem. They do sell their sodium cells for almost the cost of new oem.
     
    #8 rjparker, Jan 25, 2026 at 5:58 PM
    Last edited: Jan 25, 2026 at 6:04 PM
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  9. PriuSocal

    PriuSocal Member

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    I see, they did report to replace the 12v battery but not HV. I guess the MPI means nothing when it comes to the serious codes then.
     
    #9 PriuSocal, Jan 25, 2026 at 6:00 PM
  10. rjparker

    rjparker Tu Humilde Sirviente

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    A battery test is quick and does not require a scanner.

    Even if you paid for a PPI (pre-purchase inspection) which would include a scan, a P0A80 is replace hv battery for them.
     
    #10 rjparker, Jan 25, 2026 at 6:03 PM
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  11. PriuSocal

    PriuSocal Member

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    Thats def true, they dont troubleshoot they just replace. Well I look forward to to taking all the help you can to help me figure this one out as unlike most mechanical issues, this is uncharted territory for me. Do you suggest i look into the battery fan possibly being dirty? I ask since some say it can cause the p0A80 code and others say it wont,.
     
    #11 PriuSocal, Jan 25, 2026 at 6:14 PM
  12. PriusCamper

    PriusCamper Senior Member

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    I'd love to know if your Autel works with other apps, like Dr. Prius... If not, the OBD2 readers that work only cost like $20: http://www.ebay.com/itm/265484403768

    As long as you can clear codes while driving and hybrid battery temp doesn't get too hot, you can keep using your car while we walk you through getting ready to replace a module. Are you up for doing work like that?
     
    #12 PriusCamper, Jan 25, 2026 at 6:54 PM
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