P0A7A-325 and P0A75-341 on 2005 Prius

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Bart A Hammontree, Apr 2, 2025.

  1. Bart A Hammontree

    Bart A Hammontree Junior Member

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    Hi

    My 2005 Prius with 300+K miles had codes P0A7A-325 and P0A75-341 hit shortly after leaving the house. The car went into limp mode and had very little power. I read the codes with a techstream laptop, and after shutting the car down (but not clearing the codes) the dash warning lights went away and it started running normally. I took it for a long drive and it seems to be fine now.

    Both codes seem to be inverter related and I have had the inverter off the car several times while working on the ABS pump. The coolant levels seem good on on the inverter and I did bleed the air out of the system.

    Any ideas on where to start?

    Thanks
     
    #1 Bart A Hammontree, Apr 2, 2025
  2. MAX2

    MAX2 Active Member

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    If Techstream gave error code numbers when connecting, you could save screenshots of these errors on your laptop, and also view key parameters when errors were recorded.

    Now you can only view the manual for these errors and hope that they do not recur.

    https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/21bpm/dtcc4000.pdf

    https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/21bpm/0a7a325.pdf

    https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/21bpm/0a72326.pdf
     
    #2 MAX2, Apr 3, 2025
  3. Bart A Hammontree

    Bart A Hammontree Junior Member

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    I found someone local selling an inverter for a reasonable price so I decided to try that. I also replaced the inverter coolant pump since it was making some noise. Not sure which one fixed the problem but no more inverter related code. I am going to try and put some miles on it next week to be sure it is fixed.

    Thanks
     
    #3 Bart A Hammontree, Apr 5, 2025
    bisco and Brian1954 like this.
  4. Bart A Hammontree

    Bart A Hammontree Junior Member

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    Hello - well I guess it wasn't fixed. I drove it about a week with no issues then I got a the following codes at startup a few days ago - P0A08-264, P3108-535, C1310. These are different codes than I was getting before I replaced the inverted, but one (P0A08-264) is still an inverter related code.

    I decided to start with the P0A08-264 DC-DC converter status circuit troubleshooting first and I made it to step 12 in the testing where it instructed me to measure resistance between the inverter C5-4 plug pin and body ground. It says it should test at 100-140 ohms, but I am getting open circuit. I assume this is pointing to an issue with the plug or the wiring harness vs the inverter, but not sure of next steps to try and fix it.

    Does anyone have a wiring diagram showing where the wire from C5-4 goes? The plug looks good so I thought I would start by trying to test for continuity on the wire if I can find the other end.

    The car seems to run and drive fine, but does have the red triangle on the dash. The code comes back immediately when I clear it. Also the 12V battery checks out at 12.4V when the car is off, and 13.8 when the car is running.

    Thanks
     
    #4 Bart A Hammontree, Apr 12, 2025 at 1:40 PM
  5. pasadena_commut

    pasadena_commut Senior Member

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    I can't speak to the rest of it, but those indicate a healthy 12V. The 12.4V shows that it is somewhat discharged but the 13.8V indicates the battery is in pretty good shape. The one in my car is in less good shape and reads 14.1V when the car is running (starts at 14.5V for a fraction of a second, like, don't blink, and falls to 14.1V over several seconds, then stays there).

    Be aware that if the car does not run for sustained periods of time the 12V will eventually discharge too far and it will be damaged. Working on the car when it isn't running, with doors opening and closing and the like, will also drain the 12V. So keep an eye on it and if it gets too low attach a 12V battery charger with an AGM setting to it directly to the battery. Note that at least the charger I have is too stupid to handle charging the 12V if the car was just on, the surface charge confuses it, so the headlights must be turned on for 10s before starting the charger.
     
    #5 pasadena_commut, Apr 12, 2025 at 7:46 PM
  6. mr_guy_mann

    mr_guy_mann Senior Member

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    Here's the circuit. The tests don't mention that the 100-140 ohms is through the hybrid control ecu. (I don't know if that's the actual value on a working car).

    You might also want to check that a "full" 12V battery power is present at the converter (from DC-DC S fuse) and hybrid ecu (from HEV fuse). hybrid%20NOD.jpeg hybrid12Va.jpeg hybrid%2012Vb.jpeg

    Posted via the PriusChat mobile app.
     
    #6 mr_guy_mann, Apr 13, 2025 at 9:27 AM
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