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I think I just blew my second inverter in a row... Help?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by suirprius, Jul 5, 2022.

  1. suirprius

    suirprius New Member

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    This is my first post, but I have gotten a lot of help by lurking here over the years, so first off thanks to the community for all the knowledge and experience shared. If you guys can help me out one more time and get this car on the road again, I will be so incredibly stoked. Here's my situation:

    About a year ago, my wife's 2005 Gen 2 started showing the red triangle and intermittently not going into IG-ON mode. Usually, it would work after waiting a while. Occasionally, the 12v auxiliary battery would become FULLY drained, sometimes even after a day of driving (down to 3 or 4 volts, but its a deep cycle AGM battery so I didn't replace).

    This was an inconvenience, but at the time I didn't have a code reader that would work on the Prius, so we just dealt with it. Then, we went out of town for a month, and the folks we asked to watch the car ended up having to jump it a lot... and when we came back, it was totally dead, non-responsive, no lights, no start nothing. So I charged the aux battery which was drained down to 3V, and started going through all the fuses. I tested and replaced several (HEAD I think it was called, and a few others), and the 120A MAIN fuse in the engine compartment. This brought the car back to life, but it now had the full constellation of death on the dash board. I now had techstream and a cable, so I read the codes, and followed the Toyota FSM troubleshooting which led me to the Inverter being the culprit. The codes were:

    P0a08 dc/dc converter status circuit
    P0a09 dc dc converter status circuit low impact
    C1310 HV system malfunction
    B2775 Interior Verification to theft deterrent ecu / smart key eco

    So I bought a used inverter and installed it. This immediately cleared the error codes, and the car drove like normal for several months. However, after a week or so a new set of error codes with red triangle showed up:

    P3000 Battery Control System
    P0A85 Cooling fan control circuit low
    C1310 HV system malfunction.

    Again, I went through the FSM walkthrough for these codes, and found two problems: 1) the battery fan was bad, and 2) corrosion on a wire harness between the battery fan and the rear of the car. I replaced the fan with a new one and cut out the corroded wire and soldered and insulated it. This cleared the codes.

    Then, a few days ago (about 1.5 months after fixing the fan issue), while my father-in-law was driving the car, he heard a 'pop' and all the dash lights lit up. The current error codes are:

    P0A08-264 dcdc converter status circuit
    P0A78-279 drive motor A inverter performance
    P0A94-555 dcdc converter performance
    P3108-535 Lost communication with ac system control module
    P1498 communication malfunction A/C inverter local


    If its helpful, I have screen shots of the techstream freeze frame information, but I'm not a mechanic and am sufficiently ignorant that I don't know what to do with it. I suspect there must be some underlying electrical issue that is behind this that I missed when I replaced the inverter the first time, but I'm not sure what. Has anyone dealt with this kind of repeated situation before? Or is this really a separate issue? Any and all wisdom you guys have to pass on is truly appreciated. I want to keep this car on the road if I can.

    TL;DR:
    During normal city driving, there was a loud pop, and the following codes showed up. This is after replacing the battery fan, inverter, 120A MAIN fuse, and cleaning and soldering a corroded connection in battery fan circuit:

    P0A08-264 dcdc converter status circuit
    P0A78-279 drive motor A inverter performance
    P0A94-555 dcdc converter performance
    P3108-535 Lost communication with ac system control module
    P1498 communication malfunction A/C inverter local
     
  2. Tombukt2

    Tombukt2 Senior Member

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    That's funny I had this exact behavior and all of these codes with a crap battery in a generation 3 that I had just replaced an engine in and the HV battery had sat about close to a year the 12 volt had been taken out and putting in another Prius because I knew it was going to sit when I got a reman HV battery from Dr Prius in Virginia all that mess went away I even thought I was going to have to replace my air conditioning compressor like the code you have now I left it unplugged for a week and then just one morning before I touched the car got the remote near the car anything I plugged up the orange plug to the electric air compressor for the AC got in the car drove down the road and put it once I was underway it's worked and I've not looked back since I knew my inverter wasn't bad because it's extremely rare for them to go bad and I was putting out amps and power and all that and it didn't seem low once I changed the battery in the 13 all was well and similar happened in my Gen 2 which got a brand new battery HV battery
     
  3. suirprius

    suirprius New Member

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    So in your case a bad hybrid battery was the culprit? Replacing the hybrid battery resolved the issue for you? Did you also have the inverter, 12V aux battery, and battery fan issues I had earlier or just the dash lights and codes that I currently have? Thanks for the help!
     
  4. TMR-JWAP

    TMR-JWAP Senior Member

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    With these codes:

    P0A08-264 dcdc converter status circuit
    P0A78-279 drive motor A inverter performance
    P0A94-555 dcdc converter performance
    P3108-535 Lost communication with ac system control module
    P1498 communication malfunction A/C inverter local


    I do not think I would start with replacing the hybrid battery.
    I would start with making 100% certain my code reader was correctly reading what the car is trying to tell me, before I end up chasing my tail.
    Do you have techstream?

    Possible Trouble Area

    P0A08-264:Auxiliary battery - Fusible link block assembly - HV control ECU - Fuse (for 12 V electrical equipment) - Engine room relay block - Inverter cooling hose - Water pump with motor assembly - Cooling fan motor - No.2 cooling fan motor - Wire harness or connector - Inverter with converter assembly (DC / DC converter)

    P0A78-279: Wire harness or connector - HV transaxle assembly - Hybrid vehicle motor - Hybrid vehicle generator - HV control ECU - Inverter with converter assembly

    P0A94-555: Wire harness or connector - HV transaxle assembly - Hybrid vehicle motor - Hybrid vehicle generator - HV control ECU - Inverter with converter assembly

    P3108-535: Wire harness or connector - Inverter with converter assembly

    P1498: do you mean B1498? Wire harness between hybrid control ECU and A/ C inverter (inverter with converter) - Hybrid control ECU - A/C inverter (inverter with converter)
     
    #4 TMR-JWAP, Jul 6, 2022
    Last edited: Jul 6, 2022
  5. suirprius

    suirprius New Member

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    Yes, I have techstream. And thanks, yeah it looks like the code is B1498, not P and I wrote it down wrong. How would you make sure the codes are correct? Would you just assume techstream read them correctly?

    It seems like based on the intersection of all these possible trouble areas, the wire harness between the hybrid control ECU and AC inverter is a good place for me to start. Does anyone know the location of that harness offhand? Is it this:
    upload_2022-7-6_12-33-35.png
     
  6. TMR-JWAP

    TMR-JWAP Senior Member

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    If you're using techstream, I'd be pretty confident you're getting good readings! That makes life a lot easier!
    There's an online repair manual. Let me find a link for you.

    Service Manuals - Google Drive
     
  7. suirprius

    suirprius New Member

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    Thanks, I'll keep you guys posted as things progress
     
  8. edthefox5

    edthefox5 Senior Member

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    With all the dc to dc nags and a really bad 12 volt that goes dead a lot I would
    Think there’s a correlation there. First thing I would have done is replace the 12.

    Deep cell battery doesn’t mean it’s ok with going dead all the time. In fact killing it flat with a light bulb then holding it at 0 zero volts with a constant load on it will ruin it. One or 2 of those and it’s done and then will not hold a charge.
    Then and more importantly it will then put a big constant load onthe Dc to dc system.

    There’s 2 wires on the 12 volt battery the thick main B+ wire to the front fuse block and the thin wire to the dcto dc for 12 volt sensing.
     
  9. suirprius

    suirprius New Member

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    Sorry for the lag in response, Its been a busy month for me. And thanks for the advice! As it happens, I have replaced the 12v battery 3 times in the last 4 years, and I would like to figure out the underlying issue that is causing this to happen along with the other problems.

    An update: I took the car to a mechanic to get the issue diagnosed, and his opinion was that the hybrid battery was bad. He wasn't able to give me any specifics as to why this would cause the symptoms I have, or whether he thinks this is the root cause. I guess I'm not convinced he was thorough in his diagnosis. The battery passes the Dr Prius tests, and I don't have any battery-related codes.

    Are there ways that the HV battery can fail that will throw these other codes, or damage some element of the HV system without throwing a code? I'd really rather not pay for an HV battery until I'm pretty confident it is an issue.
     
  10. edthefox5

    edthefox5 Senior Member

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    3 new 12 volt battery's in 4 years? That's nuts.

    They keep going dead on you and no lights left on you checked the cabin lights at night by looking thru the window and made sure the overheads and the storage area light in the back is off at night?

    That's your issue there I would think constant heavy load on the dc to dc circuit with all the dead battery shenanigans. Must have killed your mileage. Didn't the 3 battery's in 4 years get your interest?

    Get a dc volt meter and hook it up in ammeter mode between the negative wire and chassis see whats its pulling just sitting there.

    On a dvm you must move the probe to the ammeter socket.

    And if its the original hybrid battery yeah its probably done its 17 years old lol...your mileage must suck and the battery meter on the mfd probably goes into purple bars at every light probably seeing red bars and the car is a dog to drive.

    Pull the orange safety plug on the hybrid battery unbolt the 2 high voltage wires under the inspection panel unbolt the battery box from the car and pull it out. Its going to be a corroded mess. Lots of youtubes on it and use the search forum link up top and search HYBRID BATTERY there's hundreds of posts about it as its the most posted thing on this site now.

    EVERYONE's hybrid battery has failed in a G2 or is about too.