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No power to inverter water pump motor

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by SteveZ, Jun 6, 2015.

  1. SteveZ

    SteveZ Junior Member

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    I had Toyota replace my inverter water pump about two years ago under the C0U recall. About a month ago I got a P0A93 code, indicating an inverter cooling system performance issue. Figuring it was a failed inverter water pump, I bought another one and just installed it. However, it's not running (no turbulence in the reservoir), and when I connected the old pump to 12 volts, it works.

    So, what should I be looking for if there is no power to the inverter water pump, and what are the potential remedies? I see on the electrical diagram that there is an inverter water pump relay, but I don't know where it's located or how easy it would be to replace. Is there a fuse that might be blown? If so, I'm not sure which one it would be. Thanks for your help!
     
  2. xliderider

    xliderider Senior Member

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    If the old pump works, but the new pump doesn't, with only the pumps as a variable, why look elsewhere for a solution? It's right there, it's the new pump that has a problem.
     
  3. SteveZ

    SteveZ Junior Member

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    The old pump didn't work when installed in the car (the reason I got the P0A93 code in the first place). I'm sure I could pull the new pump back out and it would also probably work when connected to 12 volts. That's why I think it's a wiring/electrical problem.
     
    Kmun likes this.
  4. xliderider

    xliderider Senior Member

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    Ah, got it. Old pump works when connected to 12v off the car. Sorry.
     
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Excellent troubleshooting by applying 12VDC to the pump motor to verify its operation.

    Find the 15A AM2 fuse (located on Unit B in the main relay/fuse box) which likely has blown. If that is good, find the INV W/P relay which is in the vicinity of the fuse box located behind the instrument panel, driver's side.
     
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  6. ChapmanF

    ChapmanF Senior Member

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    I see Patrick has helped you out with the locations, but so you'll know how to find them yourself in future, there ought to be a "section F" in your electrical diagram that's called "relay locations" and it starts with some very general diagrams showing the car outline and where the major relay/fuse/junction boxes are, and later detailed drawings of each such box, showing exactly what relay and component is where (and cross-referencing the page number showing where the box is).

    When you're looking in section H at the actual diagram of the circuit you're interested in, it will identify connection terminals by numbers and/or letters in little shapes (squares, circles, ovals, ...). On the last page for the circuit you're looking at, there will be a table of those numbered connections, referencing the pages (such as in section F) where there actual locations are drawn. I recently worked through a whole example for someone else here (who happened to be looking for the circuit-opening relay, but the same methods apply).

    I have a Gen 1 so it's possible some details in the electrical diagram organization might have changed (maybe the "relay locations" section isn't F any more, or something) but if so, I'm sure the changes won't stop you learning your way around.

    -Chap
     
  7. Avi's Advanced Automotive

    Avi's Advanced Automotive Independent hybrid repair shop

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    If the car turns on, the fuse for your inverter water pump good. Can you feel the new pump running when the ignition is on? Did you follow the procedure when replacing the pump, including the bleeding part, or use a vacuum filler or air lift?

    Avi
     
  8. miguelzottoyahoocom

    miguelzottoyahoocom New Member

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    Please help me out i have a prius 2004 in which runs good no problem on it, recently around 3 months i replace the P0A93 code the inverter pump the electric one in the fender with a new dealer one and 6 months earlier i replace the other pump down the fuse box the car. my car runs well but after all day using it long tris around town the vsc lights and red triangle lights up, i scan the car and no codes on it, then next day still the same and after driving it a little lights get off if i drive the car in short trips no problem but then after driving long ones lights come on again, then also get the car scan and the code P0A93 return but the part already replace recently, also i try to purge the system but the same problem can someone help me out on getting this solve????
     
  9. S.N.S

    S.N.S New Member

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    Did you get the solution and can you share it? I’m having the same problem now.. old pump is working direct with 12v but does not when attached to the grip in the car

    What if the relay is also working?
     
    #9 S.N.S, Sep 20, 2021
    Last edited by a moderator: Sep 20, 2021