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Complete Prius noob trying to solve an Inverter catastrophe...

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by scutigera, Oct 25, 2022.

  1. scutigera

    scutigera New Member

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    Hey all… I’ve lurked around for at least a dozen hours in the past week or two. I know nothing about Priuses and suddenly found myself needing to change that in a hurry. I can’t imagine a better resource for doing so…

    My mother purchased a 2013 Prius C with 54K miles a few months ago. One previous owner, records of maintenance every 3K miles, looked/sounded/felt like a nearly new car.

    After a month or so and about 700 miles of driving, she got a series of lights and warnings that eventually led first to a sort of “limp-home” mode, then shortly thereafter to a “not-going-anywhere” mode. She’s 72 years old, and this is her first hybrid. It’s also my first hybrid as her on-call troubleshooter and occasional mechanic. We were both pretty confused. I pulled DTCs P0A78, P0A94, and P0AEF with my cheap Bluetooth reader and phone app.

    We got it towed to the nearest Toyota dealer. Their Service folks said she needed an inverter and quoted her $4,270. ($3,250 for the I/C, $1,020 labor). The Service manager cited the same 3 DTCs that I’d seen. When I asked about detail codes, I was told P0A78-286, P0A94-564, and P0AEF-275.

    We’re quite broke. That estimate is 15 or 20 times what our combined financial resources can handle.

    A couple of questions:

    1. Does the Warranty Enhancement ZE3 program apply to Prius C models? The publication mentions “Prius Vehicles” – I’m too new to the community to know if that broadly refers to (Prius + Prius C + Prius V) models or narrowly means just “Prius” models and excludes the “C” and “V” variants. If my mother’s car is part of that program, I gathered from other threads on Priuschat that the P0A94 code’s presence might be enough to get the repair covered. Anyone with experiences from a similar situation?

    2. If the above is a no-go, the only other idea I have is trying a salvage part and a DIY repair. I’m reasonable handy with things mechanical/technical. Consensus here seems to be replacing an inverter is a fairly doable DIY job. A handful of YouTube videos seem to show the same. Any counterexamples? Has anyone given it a try and had a horrible time of it?

    Many thanks for any input, folks!
     
  2. Tombukt2

    Tombukt2 Senior Member

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    Replacing the inverter is easy as all get out I would want to say most any whatever can do it but I refrain from that here you should be able to buy an inverter from a junk car from a place like LKQ for almost nothing you will see them hanging out the sides of cars where people have cut the wires and just left them while they get the wiper motor or something silly like that I have them piled up out here in the yard I don't know that I have one for a Prius c but they're everywhere I didn't realize it was a part on the sea that was known to go on the generation 2 which is just like your c with the same engine but with newer inverters my inverter on the Gen 2 is never known to go The last forever of course they're pretty heavy duty The New Ones look heavy duty . But I guess internally like everything else the parts are cheaper The capacitors etc I guess just don't hold up get that car away from the dealer back to your driveway sorry you've had to tow it or whatever twice but that right there will save you $3,000 you should be able to buy an inverter for less than $200 from a car with a been hit in the side wrecked in the rear whatever and then take that to your car at home and with a few wrenches you will swap that out and then you'll see where you're at from there I would want to say you want to look long and hard at your system and make sure there's no corrosion growing on the nuts of the batteries and the bus bars on your existing system as all this can cause similar problems so you want to make sure your battery connections to your HV battery or in ship shape condition or you may be looking at problems not in your inverter The computer can tell you the inverters output and what have you sometimes the Toyota dealers are not the most honest people on the planet they are quick to do $5,000 repairs beware of that
     
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    They're not doing you any favours on the inverter cost; MSRP for the inverter is $2528 USD:


    G920059065 - Drive Motor Inverter. Electrical - Genuine Toyota Part


    The first dealership link on the above page has a price just over $2K USD, plus shipping.

    Not sure about $1K USD for labour: the 3rd gen Prius Repair manual instruction for inverter replacement is attached, might be similar.
     

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  4. ChapmanF

    ChapmanF Senior Member

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    I don't think ZE3 does. I was surprised, because the NHTSA manufacturer communications search for the 2013 c does include a ZE3 document, but that might just be misfiling on NHTSA's part. Pulling up and reading the document does not say anything about applying to the c. The Prius c is considered its own model.

    Sometimes a different model will get its own different warranty enhancement (with some code other than ZE3) but I didn't see one for the c inverter, with a quick skim.
     
  5. Sonic_TH

    Sonic_TH Active Member

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    Is the inverter coolant pump working? maybe the inverter overheated.
     
  6. Tombukt2

    Tombukt2 Senior Member

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    I drove my Gen2 many days in summer 100 degrees outside. Even then in town it would never get my h past hand touch warm. If I got on hi way. I'd have to go about 45 miles to get to heat that I could not touch. This is feeling bottom of inverter and hoses going in n out of inverter . Inverter was fine once new pump in place. New pump is not made for this application is completely different. Looks like a hot tub circ pump.
     
  7. Elektroingenieur

    Elektroingenieur Senior Member

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    Good work collecting those; it makes the diagnosis easier. The Repair Manual (more info) has troubleshooting procedures for each diagnostic trouble code (DTC), and it also includes important precautions to reduce the risk of personal injury or property damage while working on high-voltage components, such as the inverter with converter assembly and its cabling.

    The procedure for P0AEF-275, Drive Motor Inverter Temperature Sensor “A” Circuit Low, is the simplest. This DTC is detected due to an “Open or short to GND in the motor inverter temperature sensor circuit,” and the procedure directs the technician—with no further diagnostic steps—to the Replace Inverter with Converter Assembly Parts topic, in which the DTC Malfunctioning Area Table says, for this DTC and INF code, to replace the power module intelligent transistor kit and the MG control computer with bracket sub-assembly.

    Those parts are shown in catalog Figure 84-31, HEV Inverter: the transistor kit is part number 04899-52020, list price $2,334.95, and the computer sub-assembly, G920H-52H00, $1,642.62. You’d also need other parts, such as the inverter drain plug kit, 04899-47060, $36.52. This isn’t a cost-effective repair, however: as the dealer has suggested, it’s cheaper just to replace the next-higher assembly, the inverter with converter assembly, which has current service part number G9200-59065, $2,528.08. If you’re looking for one in a junkyard, however, you might see other part numbers, such as G9200-59015, G9200-59035, or G9200-52011.

    The procedure for P0A94-564, DC/DC Converter Performance, is almost as brief. This DTC is for “Boost converter overvoltage signal detection (circuit malfunction (VL sensor)),” and the procedure directs the technician—taking precautions against high voltage, such as removing the service plug grip and waiting 10 minutes, and wearing insulated gloves—to refer to step 3 in the diagnostic procedure for (unrelated) DTC P0343-747, to check that the low-voltage connectors on the inverter with converter assembly are connected securely. If they are, we go again to the Replace Inverter with Converter Assembly Parts topic, with the same results as above.

    The procedure for P0A78-286, Drive Motor “A” Inverter Performance, has many more steps. This DTC is for “Motor inverter fail signal detection (circuit malfunction),” and it has a long series of checks all over the hybrid system. In a shop where technicians’ diagnostic time is costly, it might not make sense to do these, since the other reported DTCs point to internal failures of the inverter with converter assembly.

    In your situation, however, it might be worthwhile to take the time to follow the entire procedure, just in case those failures had some common, correctable cause that wasn’t considered likely by the authors of the other two procedures, and to make sure that a replacement inverter with converter assembly wouldn’t be damaged by the same problem. I assume you’ve already checked the coolant level—if not, see “Power control unit coolant reservoir,” Owner’s Manual (PDF), page 371—and for signs of coolant leaks, kinked hoses, and the like.

    Whether you decide to do the detailed checks, or just to replace the inverter with converter assembly yourself, I’d strongly suggest getting access to the Repair Manual, not only for the safety precautions but also for the detailed troubleshooting and parts replacement procedures, which can help avoid costly mistakes.
    I’d suggest leaving the HV battery alone for now. Granted, it’s the part of the hybrid system that’s most likely to wear out over time, but in this case, none of the Repair Manual procedures for the DTCs @scutigera mentioned lists it as a potential trouble area.
     
  8. scutigera

    scutigera New Member

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    Hey - Thanks for the input. I've looked around a bit for used and salvaged inverters and was surprised at how affordable they can be. I think I'm gonna give it a go. Good to hear that it's not an unrealistically difficult job. Take care...
     
    Tombukt2 likes this.
  9. Sonic_TH

    Sonic_TH Active Member

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    Well then, please updates us on what happens.
     
  10. scutigera

    scutigera New Member

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    Many thanks for such detailed feedback and advice. I've collected several relevant service manual excerpts in my time scouring PriusChat. Your quotes from the sections about addressing the specific faults are all new to me, though, and your whole post will be added to my thickening binder of reference materials. I've been planning on going the route of replacing the whole inverter/converter, but my mother has insisted that every possible angle that involves the job being done by a Toyota service department be explored and ruled out before turning me loose on her car. After all, how could any job that costs so much be doable by anyone but the credentialed experts that are supposed to do it? [sigh...]

    If it comes to me going the DIY route, I'll certainly heed your suggestion and gain access to the full Repair Manual. I'll probably get a month's Standard subscription to Toyota TIS and supplement it with Chilton materials if my library offers access to them.

    Surprisingly, the Toyota dealer whose Service department currently has custody of Mom's inert car is open to the idea of doing the work for us with a used inverter that we would supply. It would be on an absolutely-no-guarantee-or-warranty-on-anything basis, which is understandable. Labor charges would be the same as quoted in their original estimate - $1,020 for 6 hours. I believe that would include the 2 hours already spent on diagnostics, but 4 hours still seems like a lot if I understand the job as well as I now think I do. I assume the number comes right from a manual or database. I plan to try and lean on them to justify it, but I don't see that going anywhere.

    For now my priority is locating a suitable inverter. The estimate cited the part # G9200-59065. You mentioned those 3 other part numbers that I might see if I go to a junkyard. Is to say that those parts may be interchangeable with the -59065? I'm curious because eBay searching so far has turned up tons of purported Gen3 Prius inverter/converters, but I've only seen a few -59065s. Are there other I/C parts that can be substituted for the -59065 in a 2013 Prius C? My gut tells me to play it safe and stick with the exact part specified, lest the shop refuse to work with a different one or - of course - it ends up not working regardless of who installs it. Still, I'm curious about the existence of other part numbers and how similar they all are to one another.

    One last thing - whatever happened to the current inverter had to have a cause. I'm thinking the inverter coolant pump is a probable culprit. I had suspected it might be involved before we towed the car in - when it was still in "limp-home mode" and partially operational. I popped the cap of the reservoir while the car was powered on and showing "READY" to look for turbulence as recommended somewhere and saw none. I tried squeezing and pinching the hoses to feel for fluid motion and there didn't seem to be any. That pump should be running constantly, no? In any case, I will try to acquire a pump and supply it to the shop with the inverter for replacement. If they somehow find that doing so would be unnecessary, I'll return it. Would you (or anyone else reading this!) recommend otherwise?
     
    #10 scutigera, Nov 7, 2022
    Last edited: Nov 7, 2022
  11. Sonic_TH

    Sonic_TH Active Member

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    It seems like it was indeed the inverter coolant pump that caused the inverter to fail. 6 hours seems too much for just replacing the inverter.
     
  12. Elektroingenieur

    Elektroingenieur Senior Member

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    Try your library first, and save the $90: Chilton has everything you’re likely to need, and the text and illustrations are identical to Toyota’s Repair Manual, even if the organization is a bit different.
    One edition of Toyota’s Flat Rate Manual allows 1.5 hours to remove and replace the inverter assembly with converter (operation number 890201; NHP10 series). Chilton allows 2.2 hours for the same job.
    G9200-59015 was used from start of production to November 2014, when it was replaced by G9200-59035 (for which the catalog lists G9200-52011 as the “P/N LABEL”), which itself was superseded as service part by G9200-59065 in August 2021. As far as I know, none of these parts has been recalled or been the subject of a service campaign. They’re all specific to Prius c cars (and other models not sold in the U.S.) and not interchangeable with parts for third-generation and other Prius models.
    That’s possible—and the last thing you’d want would be to damage another inverter through insufficient cooling, if that’s what happened.
    Maybe not. According to New Car Features, the pump is actuated “over 3 levels using duty cycle control” by the power management control ECU, which also monitors it. If the pump seized up or wasn’t running as fast as expected, DTC P0C73-776, Motor Electronics Coolant Pump “A” Control Performance, should have been stored.
    The inverter water pump assembly with motor (G9040-52010) has a list price of $274.97, at this writing, and many sellers won’t accept returns on electrical parts. If the shop is a Toyota dealer, they should be able to get one, if needed—but I’d ask them, first, to use their Toyota Techstream diagnostic system to do the active test of it described in the Repair Manual procedure for DTC P0C73-776.