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Inverter “flashing”

Discussion in 'Gen 2 Prius Main Forum' started by Scott Caputo, Sep 9, 2022.

  1. Scott Caputo

    Scott Caputo Junior Member

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    I have replaced a bunch of parts in this car, (2006) including the inverter. Apparently you need to re-program It if it’s changed?


    I’ve been getting a P3004/131 code and have checked or replaced everything in the diagnostic sequence for this code, and nothing has changed. I did have a bad main battery resistor, but then went on to replace the hybrid battery computer and reset the key immobilizer, and the inverter. I got all the parts a from a parts car I have that was running fine. (I got it for the exhaust with CAT) if it’s not the inverter needing to be reset, I’m pretty sure I have a bad wire someplace. There was some evidence of rodents having been in the engine compartment.

    I read on a different thread that one must “flash” the inverter if it’s changed. What does that mean and where can I get info about that procedure? Thanks
     
    #1 Scott Caputo, Sep 9, 2022
  2. ChapmanF

    ChapmanF Senior Member

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    The different thread was in the Prius v forum. Those Gen 3 inverters contain an MG ECU that has firmware. There were recalls out (E0E for Gen 3 liftbacks, F0R for Prius v) that updated the firmware in the MG ECU.

    If you had a Gen 3, and in the unlikely event you got your hands on an old Gen 3 inverter that had never had the recall applied, you would want to take it to a dealer and have that done. You can always look at the calibration IDs shown in Techstream, and compare to the recall docs, to see if things are at the right firmware version.

    In a Gen 2 Prius like yours, there is no MG ECU inside the inverter, which is more a dumb box of transistors. It either works or it doesn't.

    When something like that happens, finding the solution often requires looking back carefully over that whole repair manual diagnostic sequence, and what results or readings you had for each of the twelve steps. Sometimes other pairs of eyes will spot things, but only if we can follow along with the details.
     
    #2 ChapmanF, Sep 9, 2022
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  3. PriusCamper

    PriusCamper Senior Member

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    The Gen2 inverter after July 2007 are different than Gen2 Inverters prior to that month... So making sure you have the correct inverter is first step. As for the need to re-program, everything in the Prius (not the FOBs) is plug and play as long as its the correct part. But yes there's all kinds of crazy posts on here from people convinced you need to flash the firmware to make things work. And there are some Toyota recalls that change the firmware in the inverter for Gen3, but nothing I'm aware of for Gen2.
     
    #3 PriusCamper, Sep 9, 2022
  4. mr_guy_mann

    mr_guy_mann Senior Member

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    What tests led you to replace all those parts? Do you have safety gloves and CAT III rated multimeter? Does a scantool show expected HV battery readings from the battery ecu?

    Looking at the code description, I assume that when the Hybrid Control ecu activates the HV contactors, that it expects to see high voltage power at the inverter- if it doesn't get that, then it sets codes.

    My first thought is, do you have full HV battery voltage at the contactor input terminals? Can you safely check that?

    Posted via the PriusChat mobile app.
     
    #4 mr_guy_mann, Sep 9, 2022
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