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P0A08 will not go away, replaced 12V - Checked all common issues

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by hoosierprius81, Aug 2, 2024 at 12:27 PM.

  1. hoosierprius81

    hoosierprius81 Junior Member

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    2008 Prius
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    My 2008 Prius with 207,000 miles has code P0A08. The car runs and drives just fine, no issues.

    I have been scouring PriusChat and everything else I can find to try to diagnosis it.
    The car has only been jumped once since I bought it. It was jumped with a jump pack correctly. This problem did not start until after that anyway

    The hybrid battery and some of the hybrid battery wiring was replaced ~2.5 years ago.
    With the Dr. Prius app, the battery does not fail the test. It says it has ~68% life left and that the voltages are normal. See screenshot below.

    So far I have:
    • Verified the inverter water pump is working (ripples in tank and can hear pump running)
    • Replaced 12V battery with new Toyota OEM battery (Old battery was reading a little low)
    • Checked 5 amp fuse on 12V positive terminal
    • Checked fusible link
    • Checked and cleaned the hybrid battery cooling fan (it works fine and is clean)
    • Checked hybrid battery computer (it looks good with no corrosion)
    The only other thing I can think of is the inverter itself being bad. I have read on here that those going bad is incredibly rare unless there is a botched jump start (which I have not had).

    I am not against replacing the inverter but I am not convinced the inverter itself is bad.

    Any thoughts on additional diagnostic steps or how to tell if the inverter itself is the culprit?
    IMG_1387.jpg IMG_1388.jpeg
     
    #1 hoosierprius81, Aug 2, 2024 at 12:27 PM
  2. bisco

    bisco cookie crumbler

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    are you using tech stream?
     
    #2 bisco, Aug 2, 2024 at 12:43 PM
  3. hoosierprius81

    hoosierprius81 Junior Member

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    No, I do not have access to Tech Stream.
     
    #3 hoosierprius81, Aug 2, 2024 at 12:44 PM
  4. bisco

    bisco cookie crumbler

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    you might need the sub codes, i'm not sure.
     
    #4 bisco, Aug 2, 2024 at 12:49 PM
  5. ChapmanF

    ChapmanF Senior Member

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    Your bullet list looks as if you might have been following the P0A08 troubleshooting steps in the repair manual, but maybe you can show more of your work ... like, organize it right in the same order as the given steps, and for steps that say "measure such-and-such and it should be in such-and-such range", include what your measurement was.

    There are times when the more of your work you can show, the better the chances are that somebody else can spot what might be a clue.

    Toyota Service Information and Where To Find It | PriusChat
     
    #5 ChapmanF, Aug 2, 2024 at 1:54 PM
  6. Tombukt2

    Tombukt2 Senior Member

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    Seems to me there should be some communication error codes or something because you've got that! And the VSC light lit up and the red triangle usually that's pointing to other things but.
     
    #6 Tombukt2, Aug 2, 2024 at 4:02 PM
  7. hoosierprius81

    hoosierprius81 Junior Member

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    One
    The only error code is the P0A08... I wish there were more codes to point us in the right direction.
     
    #7 hoosierprius81, Aug 2, 2024 at 4:08 PM
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