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P0A93 code. Again. Is intermittent pumping ok?

Discussion in 'Gen 2 Prius Technical Discussion' started by Matt Biskup, May 5, 2024.

  1. Matt Biskup

    Matt Biskup Junior Member

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    2005 Prius
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    I replaced the inverter coolant pump with a Dorman from RockAuto about 10,000 miles ago. The other day, I got the P0A93 code again.

    RockAuto is replacing the pump under warranty so I'm happy about that. I now know that I should have chosen the Aisin from RockAuto or bought a Toyota factory replacement on this pump the first time this happened (maybe OEM is Aisin?).

    My question is, I see intermittent evidence of coolant pump operation when I have the engine running, in neutral (with the parking brake engaged) in 'maintenance mode lite' mode. I see coolant flow in the inverter overflow when the engine starts, but the coolant flow activity stops after just a minute or two. Again, while the ICE is running at idle.

    I haven't been able to find the expected operation parameters of the coolant pump. Should it be running continuously when the ICE is operating at idle speed? Since the ICE is idle, perhaps the inverter isn't operating, so it's not getting to a minimum inverter coolant temperature that kicks on the pump. That's my theory.

    Does anybody have any performance range temps or conditions for the inverter coolant pump to be operating?

    I'm replacing the Dorman with the warranty replacement pump. But if it's not actually the pump, what else should I be looking for?

    I have confirmed that both electric radiator fans kick on when my air conditioning is on. The only other code currently appearing is the B0421 because I have the front end of the Prius in the garage. I have Techstream v14. Inverter temp when I was watching it while the ICE was running didn't look like it exceeded 107 degrees. Outside temp is approximately 75 degrees.

    Thoughts? Thx!
     
    #1 Matt Biskup, May 5, 2024
  2. SFO

    SFO Senior Member

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    Not OK, as the ICP should be running continuously.
     
    #2 SFO, May 5, 2024
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  3. pasadena_commut

    pasadena_commut Senior Member

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    Don't do that. Get an OEM, or at least Aisin, pump and put that in.

    When I was new to this car and naive I put in a Dorman pump, and found that it worked intermittently. RockAuto sent a replacement under warranty, and it is still sitting in a box in my garage (in case some day I need a powerful 12V fluid pump which doesn't always start when power is applied) because I wasn't going to keep replacing unreliable pumps. The OEM pump which was installed instead has been trouble free since then.

    It is a pity that the Dorman's have this "starts 99% (or whatever the number is) of the time" issue, because otherwise it is a good pump. If there was some indicator on the dash that the pump had not started it would have been easy enough to just turn the car off and back on, and it would start (statistically). Unfortunately there is no such indicator, so you find out when the inverter overheats.
     
    #3 pasadena_commut, May 5, 2024
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  4. mr_guy_mann

    mr_guy_mann Senior Member

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    Decades of experience in automotive repair have shown me that Dorman is incapable of consistently producing anything of decent quality.

    Occasionally they'll goof up and make a "good" part, but it's mostly crap.

    Posted via the PriusChat mobile app.
     
    #4 mr_guy_mann, May 6, 2024
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