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How do you jump the inverter water pump to make it run?

Discussion in 'Gen 2 Prius Main Forum' started by wbs887700, Apr 7, 2021.

  1. wbs887700

    wbs887700 Junior Member

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    I know how to jump the engine coolant water pump using the a voltmeter and the relay, but how do you jump the inverter coolant water pump? Is there a relay for the inverter coolant water pump? If so, where is it?

    I'm changing the inverter coolant and I need to make the water pump run somehow so I can bleed it of air.

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  2. ChapmanF

    ChapmanF Senior Member

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    Gen 2's runs whenever the car is turned ON. Easy peasy.
     
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  3. JJ Pen

    JJ Pen New Member

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    I have this same question in 2023. I am trying to diagnose a code P0A93 and see if the pump is running besides a "check and see if fluid is swirling in the resivoire."
     
  4. ChapmanF

    ChapmanF Senior Member

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    If it's anything like the Gen 3, you should be able to look in the live data list and see both the RPM the car wants the pump to be doing, and the RPM the pump is doing.
     
  5. pasadena_commut

    pasadena_commut Senior Member

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    Well, if the pump is sitting on a work bench you can just put 12V on one pin and ground on the other and it will run. But first attach hoses to the input and output, run them into a bucket of water, and be sure the loop is full of water (no bubbles). Don't spin the pump dry. I suppose you could do this in the car too, but as noted above, just plug the pump in and turn the car on.
     
  6. mr_guy_mann

    mr_guy_mann Senior Member

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    No, the Gen2 pump isn't like that at all. It's a "dumb" output. Whenever the IG2 feed is turned on that triggers the inverter pump relay.

    No ecu has any confirmation or feedback for the pump. All the Hybrid Control ecu can look at is inverter temperatures.

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  7. mr_guy_mann

    mr_guy_mann Senior Member

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    Well, since the pump's job is to move fluid around, I guess that seeing if it can do that would be the easiest way to confirm (some) operation.

    You can feel the pump - it should hum and vibrate slightly as it works. You probably don't have a scope and amp clamp to test pump current.

    There can be other things that can cause P0A93, such as restrictions in the cooling passages (due to crazy old coolant leaving deposit buildups), or dirt and debris clogging the air flow through the bottom part of the radiator, missing air deflectors or undershields, or corroded fins on the radiator.

    I suppose you can use a scantool to monitor the inverter and MG temperatures and see what happens (and use a thermal pyrometer or imager to test radiator temperatures?)

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