Please help with battery issues P0A80

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by MrNoodle, Oct 25, 2020.

  1. MrNoodle

    MrNoodle Junior Member

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    Hello,
    I am new to the forum looking for help. I got the infamous code P0A80 on my Gen 3 (2010) but seems that none of the other posts in this forum match what I am experiencing.
    I am getting the Yellow triangle and the engine check lights with the legend "check hybrid system". interestingly when PepBoys ran the codes they could not find any codes, but when Oreilly ran it they did indeed get only code P0A80 (same as my reading with my own OBD2 reader). No other codes were found.
    The car turns on and runs fine with the gas engine, maybe it revs a little too much.
    When running Dr. Prius app, the battery test (the one you accelerate and decelerate) cannot be completed and it stays around 65%. Using Torque pro app, the voltages don't really seem very different from each other (driving and idle).
    My 12 V battery is fairly new and reads about 14.4 V after turning on the car.

    I am planning on getting the Newpriusbattery replacement but seems that maybe you could guide me in other troubleshooting steps to make sure it is indeed the battery issue?

    Thank you very much for your help.
     

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    #1 MrNoodle, Oct 25, 2020
  2. tankyuong

    tankyuong Senior Member

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    you are supposed to read the 12v battery with car off
     
    #2 tankyuong, Oct 26, 2020
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  3. Ed Beaty

    Ed Beaty Active Member

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    "My 12 V battery is fairly new and reads about 14.4 V after turning on the car."

    That is the charging voltage the Prius is putting on the 12V battery; nothing to do with the actual health of the battery. You need to do what tankyoung says: read the 12V voltage using a voltmeter or battery tester.
     
    #3 Ed Beaty, Oct 26, 2020
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  4. royrose

    royrose Senior Member

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    After reading the 12v voltage with the vehicle off, you might try disconnecting the 12 v battery and then reconnecting it. That should clear the code. Then you might be able to run the Dr. Prius test.
     
    #4 royrose, Oct 26, 2020
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  5. bisco

    bisco cookie crumbler

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    welcome!
    you will need tech stream to nail down the p0a80. how many miles on her?
     
    #5 bisco, Oct 26, 2020
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  6. MrNoodle

    MrNoodle Junior Member

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    Thank you, I will read the 12 V battery tomorrow and report back. I have 125K miles on the prius, so not much.
     
    #6 MrNoodle, Oct 26, 2020
  7. MrNoodle

    MrNoodle Junior Member

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    Hello again, I tested the battery with the car off, it was 12.35 V.
    I also disconnected the battery for a few minutes and after connecting it again now my car's dashboard lights up like a Christmas tree and cannot shift to drive. The only positions the car let me be in is Neutral and Park.
    Please help!!
     
    #7 MrNoodle, Oct 27, 2020
  8. tankyuong

    tankyuong Senior Member

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    That voltage is low
     
    #8 tankyuong, Oct 28, 2020
  9. ChapmanF

    ChapmanF Senior Member

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    Grading on the curve of "is this a fully charged 12 volt battery?", yes, it's low.

    On the curve of "is it above the 11 volts Toyota would have you check for before continuing with diagnosis?", it passes easily; it is also probably a few tenths higher than mine would read if I went outside right now to read it, and my 2010 starts right up with no warnings or codes. 12.35 is plenty for all the computers to know what they're talking about. If the battery computer is telling you P0A80, odds are that means the detection conditions for P0A80 have been met.

    In Gen 3, "the triangle" is yellow, BTW.
     
    #9 ChapmanF, Oct 28, 2020
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  10. jerrymildred

    jerrymildred Senior Member

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    +1 to what Chap said. 12V is fine. Problem appears to be in the traction battery. P0A80 should have a sub code that will tell you which module is the problem child. Or it could be in the sensor wires.
     
    #10 jerrymildred, Oct 29, 2020
  11. MrNoodle

    MrNoodle Junior Member

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    Thank you for all your advice. So a few things happened yesterday:
    Seems that the 12 V battery was OK, it was the traction battery disconnect (orange lever) that needed to be pushed in harder that was preventing the car from shifting into drive. I disconnected the traction battery lever per one of the recommendations online.
    After that, I disconnected and connected again the 12V to clear the codes and for some reason, this time around the code was gone. I have tried multiple disconnects before where the codes could not be cleared.
    Anyways, I was able to run the Dr. Prius app battery test, this time it actually completed the test (before it got stuck at 65%) and it showed issues with module 1. Also, the battery life expectancy test shows 12% capacity so pretty sure I will need the new battery and it a matter of time the code comes back.
    Unfortunately, there is no subcode shown, just the P0A80. Could it be something else? how can I check the sensor wires?
    Thank you again for all the help!
     
    #11 MrNoodle, Oct 29, 2020
  12. Grit

    Grit Senior Member

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    Subcodes are on techstream.
     
    #12 Grit, Oct 30, 2020
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  13. pjksr02

    pjksr02 Active Member

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    Now that that's settled, read up on cleaning the EGR system (the EGR cooler and intake manifold in particular).
     
    #13 pjksr02, Oct 30, 2020
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