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.

  1. hoosierprius81

    hoosierprius81 Junior Member

    Joined:
    Jan 6, 2020
    17
    3
    0
    Location:
    Indiana
    Vehicle:
    2008 Prius
    Model:
    One
    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
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,166
    50,600
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    are you using tech stream?
     
    #2 bisco, Aug 2, 2024
  3. hoosierprius81

    hoosierprius81 Junior Member

    Joined:
    Jan 6, 2020
    17
    3
    0
    Location:
    Indiana
    Vehicle:
    2008 Prius
    Model:
    One
    No, I do not have access to Tech Stream.
     
    #3 hoosierprius81, Aug 2, 2024
  4. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,166
    50,600
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    you might need the sub codes, i'm not sure.
     
    #4 bisco, Aug 2, 2024
  5. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    25,663
    16,763
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    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
  6. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    11,169
    1,950
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    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
  7. hoosierprius81

    hoosierprius81 Junior Member

    Joined:
    Jan 6, 2020
    17
    3
    0
    Location:
    Indiana
    Vehicle:
    2008 Prius
    Model:
    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
  8. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    11,169
    1,950
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Seems that can be along the guys of the DC to DC converter which supplies your 12 volt battery if I'm not mistaken so if you're 12 volt battery is not getting charged or the computer thinks it's not getting charged I guess it could set the ABS! And possibly the VSC because then it would be on that battery backup thing that's next to your 12 volt back there on something to do with ABS backup power or something which is now not going to be getting power or something might be a big problem.
     
    #8 Tombukt2, Aug 2, 2024
  9. exstudent

    exstudent Senior Member

    Joined:
    Jul 11, 2009
    2,214
    904
    0
    Location:
    Torrance, CA
    Vehicle:
    2007 Prius
    OP may best be served by contacting Autobeyours (Scottsburg, IN), to see how much they charge for a diagnosis and repair (will be determined by the diagnosis). Highly skilled and competent people there.
     
    #9 exstudent, Aug 3, 2024
  10. hoosierprius81

    hoosierprius81 Junior Member

    Joined:
    Jan 6, 2020
    17
    3
    0
    Location:
    Indiana
    Vehicle:
    2008 Prius
    Model:
    One
    For those wondering, replacing the inverter fixed the issue and made the code go away.
     
    #10 hoosierprius81, Aug 7, 2024
    Brian1954 and bisco like this.
  11. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,166
    50,600
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    congrats!
     
    #11 bisco, Aug 7, 2024
    hoosierprius81 likes this.
(You must log in or sign up to post here.)