Moving forward on P0A94 error code

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by TheBlash, Sep 13, 2022.

Tags:
  1. TheBlash

    TheBlash Junior Member

    Joined:
    Sep 10, 2021
    2
    0
    0
    Location:
    New Mexico
    Vehicle:
    2008 Prius
    Model:
    ----USA----
    2008 Prius, 255k miles. I was driving to work yesterday when the Red Triangle, and many other lights, turned on. This is a common occurrence, as I have an intermittent P0390 "low engine power" code, which I believe is unrelated to this problem (though please feel free to chime in if you have any ideas about that code!). I pull over and check the codes and am surprised to see a new one, P0A94 "DC-DC Converter Performance."

    There are a ton of articles online, or posts here, about what that means and some about how to replace the inverter, but I have yet to find anything on how to make sure that the inverter is, indeed, bad. I am comfortable with replacing the inverter but I would like to know if anyone has any information on how to troubleshoot the inverter before I shell out the money on a replacement. Better yet, would replacing the inverter be a surefire fix for that error code?
     
    #1 TheBlash, Sep 13, 2022
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,169
    50,602
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    perhaps tech stream would have a sub code. otherwise, the troubleshooting tree is in the service manual
     
    #2 bisco, Sep 13, 2022
  3. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    11,170
    1,950
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Inverters for Gen 2s are cheap like 25 to $65 I have two or three here on the shelf
     
    #3 Tombukt2, Sep 13, 2022
  4. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    11,170
    1,950
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    And it states performance issue not dead . Maybe out put is limited because of hot fluid .Ding! Maybe not . So I'd be looking at the output of my inverter and the range of that output and what it might should or could be at different times which I imagine would come from the service manual if you're supposed to put out 150 amps and you're only putting out a hundred or something of this nature they're in lies a problem
     
    #4 Tombukt2, Sep 14, 2022
  5. TMR-JWAP

    TMR-JWAP Senior Member

    Joined:
    Aug 12, 2016
    6,404
    6,073
    0
    Location:
    Columbia, SC
    Vehicle:
    2007 Prius
    Model:
    Touring
    P0A94 has about 2 dozen possible subcodes to point you in the right direction. Are you able to look at the freezeframe data to get the subcode?
     
    #5 TMR-JWAP, Sep 14, 2022
  6. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    25,665
    16,765
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    It's rarely a good idea to try to extract very much information from a trouble code's fortune cookie. The fortune cookies never had that much information put into them in the first place. :)

    That's especially the case with a P0 code, like P0A94. Because P0 codes are standardized by SAE, all Toyota got to do was pick the existing one closest to what issue they are reporting, and be stuck with the "DC/DC Converter Performance" fortune cookie that SAE assigned to that code.

    The only real way to know what the code is telling you is to take it and the INF code to the repair manual, and look at the detection condition.
     
    #6 ChapmanF, Sep 14, 2022
  7. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    11,170
    1,950
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Must be some specs of said DC to DC converter . To compare to . I'd think .I'd imagine all those fat orange wires should have pretty specd voltages and amperage running thru them .or else performance problems would exist. One would hope anyway.
     
    #7 Tombukt2, Sep 14, 2022
  8. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    25,665
    16,765
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    They publish specs in the New Car Features manual, but it's kind of up to them what specs they publish. In the Gen 3 NCF, they give a figure of 120 amps for the converter's maximum output. I've not found that they published such a number for Gen 2, but the wire size and fusing is similar, and people testing have concluded it's similar.

    [​IMG]

    More directly useful, they do publish what the trouble codes and INF codes mean. That's in the repair manual. The repair and New Car Features manuals can be found in the same place:

    Toyota Service Information and Where To Find It | PriusChat
     
    #8 ChapmanF, Sep 14, 2022
(You must log in or sign up to post here.)