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  1. Andrew Smillie

    Andrew Smillie Junior Member

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    Hello. I have a 2004 Prius with around 240,000 miles (replaced engine). Here's my issue:

    I am getting the P0A93 code after driving around for about 20 minutes on a hot Texas day. During the winter I don't have the same issue. I have replaced the inverter and the inverter pump (Toyota OEM part). I bled the system as well to remove the air bubbles. When driving around I get all the Christmas lights on the dash and after checking the code, its again the P0A93 code. When looking at the coolant storage tank there is no disturbance. So it still seems like the flow of coolant is not happening. I am at a loss at this point. Both radiator fans are working.
     
  2. JC91006

    JC91006 Senior Member

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    If you don't see any turbulence in the inverter coolant reservoir, your pump is not working. You would need to install another one.

    Try getting them from the Toyota dealer, then you won't get into the problem with cheap counterfeit parts
     
  3. Andrew Smillie

    Andrew Smillie Junior Member

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    Bought from the Toyota dealer and replaced one that was (likely) working as well.
     
  4. JC91006

    JC91006 Senior Member

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    Did you drain the coolant when you installed? Some have had the pump burn out before coolant gets to the pump. Dealers now just simply clamp the hoses and change the pump. It's way faster and they don't have to worry about coolant not getting to the pump when it first turns on.

    If you bought the part less than a year ago, it would be under warranty
     
  5. Andrew Smillie

    Andrew Smillie Junior Member

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    I didn't drain the coolant. I just clamped and replaced. I bought the new inverter part yesterday. I bought a new (Dorman) last year and I replaced it thinking that it might be the issue. But I am really not sure if it was. The hoses are all vibrating and the pump is on and also vibrating. When I bleed the system, how fast should the coolant flow? Its more than a trickle but its not really pumping that hard either. Isn't the fact that the system is bleeding with coolant running through it a sign that the pump is working as well?
     
  6. JC91006

    JC91006 Senior Member

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    Maybe there's a kink in your hoses? What method are you using to replace it? remove headlight or propping up the inverter?

    You can look inside the inverter reservoir, the coolant should look like it's slightly boiling, it's a good amount of movement in the fluid
     
  7. Andrew Smillie

    Andrew Smillie Junior Member

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    I am looking at the hoses....the ones that I can see are fine. But I know there are some down below which I haven't really looked at. Yeah its not moving at all. But it wasn't with the old inverter pump. I just don't think its the pump at this point and am trying to figure out what else it could be.
     
  8. JC91006

    JC91006 Senior Member

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    If you can feel the pump is on (has power going to it), then it would be your hoses. Did you switch the hoses?
     
  9. Andrew Smillie

    Andrew Smillie Junior Member

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    I got down under the car and all the hoses are routed correctly according to the diagram. The one at the bottom is vibrating when I touch it but not the other and not the one leading to the inverter radiator. I feel like there is a blockage somewhere. Perhaps enough of a blockage that is allowing the system to circulate during the bleed but not enough to cool the inverter while driving?
     
  10. TMR-JWAP

    TMR-JWAP Senior Member

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    Is this the diagram you referenced?

    ICW flow.jpg
     
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  11. Andrew Smillie

    Andrew Smillie Junior Member

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  12. Andrew Smillie

    Andrew Smillie Junior Member

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    I feel like this might be an electrical issue. Could the pump have enough juice to bleed and turn on, but not enough to circulate the coolant properly?
     
  13. TMR-JWAP

    TMR-JWAP Senior Member

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    When you bleed it, you're connecting one end of a small hose to the "brake type" bleeder fitting directly in front of the inverter and putting the other end of the hose into the inverter reservoir? The cracking open the bleeder and it's getting good flow?

    Are you running the pump while in ready or when in IG-ON (2 presses of power button with no foot on brake).

    I've done about a dozen or so of these pumps and on a few of them, I've had to do some hose squeezing to get the pump to prime. The pump totally changes sound when it's actually moving coolant. Very rough when not moving coolant, very smooth when flowing.
     
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  14. Andrew Smillie

    Andrew Smillie Junior Member

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    Yes correct. That is how I bleed it (not in ready mode....2 presses of the start button). I get decent flow (same as the youtube videos I watch). It doesn't pump hard but its not a trickle either.
     
    #14 Andrew Smillie, Jun 13, 2021
    Last edited: Jun 13, 2021
  15. TMR-JWAP

    TMR-JWAP Senior Member

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    There's an electrical connector directly above and just to the passenger side of the fuse box. It only has one wire and is the power path for the pump. I've had this connector be a bad connection on one pump. Just unplugging it, cleaning it and plugging it back in made a significant difference in pump speed. Maybe check that.

    When you swapped inverters, did you keep the same inverter reservoir?
     
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  16. Andrew Smillie

    Andrew Smillie Junior Member

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    I will try that later today. I was looking at it but didn't do anything. I checked the fuse and it's fine. I am using the same reservoir. The new(used) inverter didn't come with one
     
  17. Andrew Smillie

    Andrew Smillie Junior Member

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    Should there be only 1 prong on this?
    upload_2021-6-13_15-49-3.png
     
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  18. mr_guy_mann

    mr_guy_mann Senior Member

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    Yes- that is the ground wire that goes to the pump.

    I have seen one that have had heavy "silicate deposits" in the cooling system. That needed some pretty good flushing to clean things out

    Posted via the PriusChat mobile app.
     
  19. Andrew Smillie

    Andrew Smillie Junior Member

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    Ok well I cleaned it up and re-seated it. No change. If I took this car to the dealership and asked them to analyze the lack of flow I wonder how much they will charge me. I am getting to that point. I don't know what else to do.
     
  20. James345

    James345 Junior Member

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    hey you ever fixed it?