Toyota first timer with a rare error code ‘Insulation resistance transaxal zone’

Discussion in 'Gen 4 Prius Care, Maintenance and Troubleshooting' started by Mivadi, Mar 9, 2020.

  1. Mivadi

    Mivadi New Member

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    We picked up our first Emotional Red Toyota Prius 2016 with all the bells and whistles on it, up last Thursday and we’re quite happy with it

    upload_2020-3-9_22-32-1.jpeg

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    ....until Saturday when we got a nice orange warning signal on our display accompanied by three error messages:
    1. Pre-crash safety malfunction
    2. ICS malfunction
    3. Hybrid system mal function


    Of course straight away back to the dealer where they checked the system which returned with a P1C7E49 errorcode which related to the Hybrid system error and according to the mechanic the other two where a result of this one.

    The mechanic never saw this one though and while he checked the reference manuals, made some calls and checked more guides, he was still quite unsure about it and became quieter and quieter...

    In the end he tried to reset the system three times but it always came back with the same error. Although the car still worked on the ICE only, he didn’t want me to leave with it and come back on Monday so we we’re talking about a loaner when we decided to give it one ore try.

    This time the error didn’t popup again even after a short testdrive, so I took the car with me again.

    Today, Monday, the head mechanic called me as they discussed the error and although the error didn’t come back, they wanted to have the car back in the shop to check it completely.

    Good thing of course and although my very first experience with Toyota got somewhat bruised as you might understand, the actions of the dealer at least gives me the idea they are serious about what they mean.

    The thing however is that when I Google on the error I don’t get a lot of hits and what I read doesn’t sound too good...

    “Insulation resistance of the hybrid battery / EV voltage system decreased (transaxle zone)” source: some France site translated by Google.

    I am no car tech and have absolutely no Hybrid knowledge, but this does sound like a potential very serious issue to me. Especially when taking into account the low amount of hits I get in Google, which could be a good indication on how rare something is...

    Now I do have a 3 year warranty on the Hybrid parts from Toyota, but I have no clue whether the above mentioned parts belong to those. Sounds like it does, but than again the transaxale isn’t a real hybrid part.

    Next week the car will go to the dealer and hopefully they can tell me something more, but as you might understand I’ve got some bad feeling about this here and was hoping whether someone here has any idea what this error actually might mean.

    For now the car runs normal again, but I was planning to use it for at least the next 7/8 years, but not if I keep having some dark feeling something ominous might happen at any time.... don’t want to run any risks especially as our small kids are regularly in the car as well.

    Any thoughts about the error or even some uplifting message about the reliance of Toyota is more than welcome as I need to find some positive thoughts again...
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    #1 Mivadi, Mar 9, 2020
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  2. pjksr02

    pjksr02 Active Member

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    How many miles/km are on the car?
     
    #2 pjksr02, Mar 9, 2020
  3. CooCooCaChoo

    CooCooCaChoo Senior Member

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    ICS is the system used to detect stuff around the car and has nothing to do with the hybrid system. This system uses a bunch of sensors placed around the car. Looks like dimples on the bodywork.

    Pre-crash safety system also has nothing to do with the hybrid system. It uses a radar and front facing camera.

    And that hybrid malfunction is pretty general that needs to be scanned by a TechStream code reader.

    Is this a Toyota dealer that you are getting it serviced at?
     
    #3 CooCooCaChoo, Mar 9, 2020
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  4. ChapmanF

    ChapmanF Senior Member

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    Pretty sure the transaxle counts as a real hybrid part, considering that both electric motors are inside it. The best place to confirm coverage is the language in your warranty document. You would not be within three years on a 2016, would you? Or is this a certified-preowned purchase, accompanied by a warranty? In any case, there should be clear language somewhere to pin down the coverage and limits. In the Netherlands it might not be identical to what I can look up in the US.

    The problem is not super common, but it is also not mysterious or unheard of. There is a high-voltage power system in the car, extending from the traction battery in the rear all the way up to the underhood area, the electronics inside the inverter/converter box, the transaxle itself, and the air conditioner.

    All of the wiring and components in the high voltage system are heavily insulated to avoid any of that voltage appearing on the car's metal body or low-voltage circuits anywhere. And the car constantly tests that: whenever it is on, it generates a distinctive small AC waveform and superimposes that on the high-voltage DC from the battery, and it monitors the car's body and low voltage wiring for any sign of that distinctive waveform. That allows it to catch any decrease in the insulation effectiveness around the high-voltage system, while the decrease is still very small.

    If it detects a problem, one of the car's computers goes further, and works to narrow the location of the problem to one of several "zones": the battery and its nearby wiring, the underfloor wires from there to the front of the car, the electronics area, the transaxle area, or the air-conditioning compressor or wiring.

    Your car has traced the location of the problem to somewhere in the transaxle area. That could be the transaxle itself, or perhaps some of the wiring near it: the repair manual (more info) should include a diagram of what is included in each "zone".

    The upshot should not be several years of dark ominous feelings. It should just be to get the problem located and fixed. It will take some technicians a short time using a megger tester to pin down just where in the 'transaxle zone' the issue is. The repair could be anything from minor attention to a connector, to replacement of the transaxle, depending on what is found. If the transaxle is covered under warranty, no worries.

    After the car is fixed, there won't be ominous music playing anymore.
     
    #4 ChapmanF, Mar 9, 2020
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  5. alanclarkeau

    alanclarkeau Senior Member

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    One thing I'd be asking is that the recall has been carried out on the wiring harness located above and toward the rear of the inverter.

    The dealer should be able to track the error with diagnostics they have. I had a series of malfunctions (about 8 or 10 of them) flash up on my screen soon after I bought it - turned out to have been a single malfunction of the brake light sensor. A lot of driving functions are tied into pressing the brake pedal - like the POWER button, the gearchange as well as quite a few brake and handling situations. A new sensor 3½ yrs ago, and no problems ever since.

    Do you know if the car has ever been in an accident?
     
    #5 alanclarkeau, Mar 10, 2020
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  6. Mivadi

    Mivadi New Member

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    Thanks for your thoughts very apreciated!

    We've purchased the car at an official Toyota dealer including a 3 year hybrid warranty and 6 months full coverage on other parts, plus another year on the hybrid parts as it was also still within the warranty period from Toyota.
    The car right now has 29800 km on it, so about 15800 miles and this was also part of the reason why we bought as we want to use it for at least 7/8 years. The car got checked and they confirmed (in writing) it has never been in an accident so no worries there.

    It sounded weird to me that some sensor related to safety would give an error caused by the hybrid system, but as said my knowledge is pretty limited in this area and when reading about all the weird issues which might arise due to a faulty 12V battery it doesn't sound that far fetched... I'll keep a close eye on it and request all the readouts etc once I get it back from the dealer.

    I also mailed Toyota Europe whether they could confirm which recalls have been completed on the car and they send me back a printscreen of the data in their database.
    upload_2020-3-10_13-55-8.png
    So looks like harness at least has been checked, but googling the resolution LGG58D does not give any answers, so whether they taped or replaced the entire harnass is not clear right now. This is however something I'll definetly ask.

    One thing though is somewhat surprising and that is the fact most recalls where done some considerable time (4th column is repaired date) after they where announced, but nevertheless they have been done.

    The dealer is one of the best Toyota dealers in the Netherlands, so it must be they know what they are doing. The fact that the main mechanic called with the message they wanted to make absolutely sure there's nothing wrong does feel ok so let's see where this goes...
     
    #6 Mivadi, Mar 10, 2020
  7. CooCooCaChoo

    CooCooCaChoo Senior Member

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    You can also put the VIN into the Toyota owners website and it will tell you what has been done to it.
     
    #7 CooCooCaChoo, Mar 10, 2020
  8. Prodigyplace

    Prodigyplace 2025 Camry XLE FWD

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    Does that work for non-US cars?
     
    #8 Prodigyplace, Mar 10, 2020
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  9. Mivadi

    Mivadi New Member

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    Unfortunately the Toyota US owners site does not work for Europe VIN’s. Tried and came up with an error.
    Toyota seems not to have a similar service in Europe, but they responded on my mail within 3 hours so that’s pretty decent!
     
    #9 Mivadi, Mar 10, 2020
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  10. alanclarkeau

    alanclarkeau Senior Member

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    "So looks like harness at least has been checked, but googling the resolution LGG58D does not give any answers, so whether they taped or replaced the entire harnass is not clear right now. "

    - from what I remember of that recall - almost everyone's was taped. In fact, I don't recall any which had been damaged and needed replacing.
     
    #10 alanclarkeau, Mar 11, 2020
    Last edited: Mar 11, 2020
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