Inverter pump failure with no symptoms?

Discussion in 'Gen 2 Prius Technical Discussion' started by ProspectivePriusPeruser, Apr 30, 2020.

  1. ProspectivePriusPeruser

    ProspectivePriusPeruser Junior Member

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    Hello all.

    I was a passenger in another Prius and noticed a whirring noise on startup that's absent from mine. I checked my inverter coolant reservoir for turbulence and noticed there's no movement at all in there.

    I don't have any warning lights and the car seems to be running perfectly fine. As far as I can remember mine has never made the noise that I'm now assuming is the pump, but I have driven it on some fairly warm days with no noticeable problems.

    Is it likely that my pump is shot and I've just gotten very lucky so far, and are there any other definitive ways to tell if there's a problem?

    Cheers.
     
  2. SFO

    SFO Senior Member

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    Try touching the pump with a finger or a rod (pencil, stick, etc), if you feel a vibration then it should be working.
     
  3. dolj

    dolj Senior Member

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    Even if vibration indicates the pump is running, it still might not be working. If there is no discernible movement, this to me is a better indication of whether the pump is working or not.
    Yes and maybe not so much luck as a series of events that have worked in your favor. If there is not a great load on the inverter then it can run quite happily. The inverter coolant circulation pump (ICCP) failure is not monitored so it will not trigger a DTC, but if the inverter gets too hot that is what triggers a DTC (P0A93 and/or C1241, maybe others) to alert you to the situation. When this happens you will be pulling over and waiting at least 20 min for the inverter to cool down so you can go again and probably sticking to 45 MPH or less.

    You don't really want to run in this condition in the long term, because if the pump goes out in style and shorts out, it will blow the AM2 fuse and the dash and MFD will go out and you will be dead in the water until you isolate the ICCP and replace the AM2 fuse.
     
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  4. bisco

    bisco cookie crumbler

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    i don't recall a whirring noise on startup
     
  5. TMR-JWAP

    TMR-JWAP Senior Member

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    You don't really want to run in this condition in the long term, because if the pump goes out in style and shorts out, it will blow the AM2 fuse and the dash and MFD will go out and you will be dead in the water until you isolate the ICCP and replace the AM2 fuse.

    This x2

    i don't recall a whirring noise on startup


    Try just pressing the power button 2x with your foot off the brake. The ICWP should run and the rest of the car will be quiet (as long as radio and fans are off). Makes it much easier to hear the pump motor running and makes makes the ripples more obvious since there wont be vibrations from any other source.
     
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  6. bisco

    bisco cookie crumbler

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    thanks, i will try that
     
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