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HV inverter and HV ECU malfunction codes

Discussion in 'Generation 1 Prius Discussion' started by JL2001, Jun 24, 2009.

  1. JL2001

    JL2001 New Member

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    My 2001 gets up to whopping speed of about 2 MPH with whining sounds and then the red triangle comes on.
    Has anyone had experience with DTC codes P3100 and P3125.
    I've tested the inverter and HV ECU and they function properly in a friends 2001.
    I'm now steering towards the battery pack. Possibly current starvation due to corroded terminals. Wouldn't this cause a P3000 / 3001 DTC though?
    Haven't taken the battery out yet to check this theory.
    Any ideas are muchly appreciated.
    Cheers,
    John
     
    #1 JL2001, Jun 24, 2009
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi John,

    Good idea to swap the inverter and hybrid vehicle ECU into your friend's car. How many miles and how many starts (on/off) did you log with those parts in your friend's car? (Want to make sure that the parts logged enough use in the other car to prove they work well.)

    Once you have determined that the inverter and HV ECU are good, then my guess would be the transaxle is bad assuming the whining sounds come from the drivetrain. However, you could swap the traction battery to rule that component out. If the battery was bad I would expect DTC P3006 (uneven module SOC) to be logged.
     
    #2 Patrick Wong, Jun 24, 2009
  3. JL2001

    JL2001 New Member

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    We did not test the inverter extensively but the test involved putting the test car under heavy torque on a hill in order to draw current through the mosfets. (I suspected they would be bad since the coolant pump is not circulating but I was wrong ... unfortunately).

    I'm now only getting DTC P3125.
    Does the coolant pump have any sensors on it aside from resultant over temperature?
    Thanks Patrick,
    Regards,
    John
     
    #3 JL2001, Jun 24, 2009
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi John,

    The coolant pump itself does not have sensors. The inverter has temp sensors within.

    If you didn't run the test car over several start/stop cycles then it is possible that an error would not have been logged. Some DTC do not get logged until the problem happens two times or more.

    Your friend may not be happy about the prospect of putting your inverter back in. If you can presume upon the friendship then I suggest you do so and leave the inverter in your friend's vehicle for several days (and being driven a few hundred miles at minimum, under hot weather conditions) to confirm that it is working properly. What if an intermittent problem exists...
     
    #4 Patrick Wong, Jun 24, 2009
  5. JL2001

    JL2001 New Member

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    'The inverter has temp sensors within."

    Hi Patrick,
    The test was a bit more involved. We disassembled the inverter and tested each part separately since I expected the fault to be overheated mosfet modules.

    The temp sensors I suspect are in the mosfet modules since they are bolted to the coolant heatsink jacket.

    Is there any history on what fails first, inverter or transaxel when the coolant pump stops working? If its the transaxel, what typically gives up under heat. If its MG2, you would think the windings would be unravelling and triggering a short DTC.
    Regards,
    John
     
    #5 JL2001, Jun 24, 2009
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi John,

    I believe that the inverter is more susceptible to overheating damage (and therefore will fail sooner) than the transaxle.
     
    #6 Patrick Wong, Jun 24, 2009
  7. JL2001

    JL2001 New Member

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    I had the car towed to a repair depot that fixes all the prius taxis locally. (150 2nd gens) These guys have seen it all.
    The DTC codes are now :p3125 303 287
    Their saying the transaxel is NG even though everything still points to the inverter. ???

    Does anyone know the function of the 2 boards on the underside (in a siliconed rectangular pan) of the inverter.?
    I did not test these boards yet.
    The 12V aux battery plugs onto one of the boards so I'm guessing its the down converter from 276 to 12v.
    Regards,
    John
     
    #7 JL2001, Jun 27, 2009
  8. JL2001

    JL2001 New Member

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    Wow what a neat car.
    Works well with the used transaxel from the wrecker.
    Time now to do the EV mode hack.
    Thanks for all the help on this forum.
    Regards,
    John[​IMG]
     
    #8 JL2001, Jul 4, 2009
  9. j_sooner

    j_sooner New Member

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    John,
    That is the DC/DC converter, I just replaced mine. There was no DTC, the 12v was not getting chaged and small battery light was on next to check-Ing. Once I replace the PC/board from donor, the battery is repoting 13.5v all the time..
    I will be replacing my transaxle some time once I find a replacement.
    Regards,
    j.
     
    #9 j_sooner, Jul 16, 2009
  10. tochatihu

    tochatihu Senior Member

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    JL2001, your local repair shop that does the taxis sounds very interesting - could you tell us more about that?
     
    #10 tochatihu, Jul 17, 2009
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