Red triangle. Waiting on code reader... battery? Inverter cooling pump?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by cyberfunk, Jun 13, 2023.

  1. cyberfunk

    cyberfunk New Member

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    I got a red triangle yesterday (actually just the check engine and the orange icon on the screen as my dash was off, but later the red triangle when I got the dash on). A/C went warm for a bit right around the same time, but otherwise no issues.

    Used my wife's basic coder reader, which gave $07e8 - cooling system. I now have an Autel AP200 on the way, but it could be a week. Trying to figure out if there's anything I can do right now while I wait.

    Looking at other threads, the battery or the inverter cooling pump seem likely. I tried checking the fluid resovoir for the cooling system after startup and did see a little turbulence and could feel the fluid in the hose. Is it possible that the pump started working again but is still what caused the code originally? Or can I rule it out?

    The battery doesn't show any issue on the car's built-in diagnostic screen, but I gather it might still be the problem. Anything else I can check? Do any of the chain auto part stores have code readers that would give more info?

    Thanks!
     
    #1 cyberfunk, Jun 13, 2023
  2. Tombukt2

    Tombukt2 Senior Member

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    Is the car on the multifunction display red or green? Check the AM2 fuse the connector and plug on the flat pancake inverter pump and you're looking in the reservoir that's attached to the silver inverter hybrid synergy drive the big silver cover not the radiator.
     
    #2 Tombukt2, Jun 14, 2023
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  3. bisco

    bisco cookie crumbler

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    You can check the pump by looking for movement in the reservoir.

    The car only looks at the 12v, not the hybrid battery.
    If there’s movement, you’ll need the codes
     
    #3 bisco, Jun 14, 2023
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  4. cyberfunk

    cyberfunk New Member

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    Thanks for the ideas!

    -Checked AM2 just now and it's good.
    -Confirmed that I was looking at the right (hybrid cooling system) resovoir. There was some movement when I checked yesterday.
    -The car on the center display was red/orange.

    Shipping estimate on the reader is better than originally estimated, so I hope I'll have the codes tomorrow or Friday at the latest.
     
    #4 cyberfunk, Jun 14, 2023
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  5. cyberfunk

    cyberfunk New Member

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    Ok, code reader arrived and it is indeed P0A93.

    I checked the resovoir again and even felt the pump--there is definitely movement of fluid and vibration from the pump. The fluid level in the resovoir is above "low" line but not to "full."
     
    #5 cyberfunk, Jun 15, 2023
  6. mr_guy_mann

    mr_guy_mann Senior Member

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    That code means "the inverter got too warm". 99% of the time it's a problem with the pump. Usually the pump "dies and never pumps again". Or it "dies, shorts and pops the AM2 fuse".

    Sometimes the pump can intermittently "not pump" (esp. aftermarket units). Then next ignition cycle it does pump.

    Otherwise it can be an inverter coolant hose is twisted or squished. Maybe there's lots of dirt and leaves restricting airflow through the bottom 1/4 of the radiator.

    You may have to inspect the entire inverter cooling system, and use a scantool to monitor inverter temperatures while driving the car.

    Posted via the PriusChat mobile app.
     
    #6 mr_guy_mann, Jun 17, 2023
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  7. pasadena_commut

    pasadena_commut Senior Member

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    You might try unplugging the connector to the inverter pump and inspecting it. If it is corroded or dirty you might get intermittent pump function. Also, while it is off, apparently some pumps fail by leaking into that connector, so if it is wet you know that must be replaced. Is it an OEM pump? I had a Dorman at one point and it had the really annoying property of not starting every once and a while. Nothing like an intermittent failure to ruin your week. The replacement OEM pump has been 100% reliable. Since you are probably going to end up getting a pump, be sure to get it from a dealer so that you know it is genuine, there are fake OEM products on Amazon, and you don't want one.
     
    #7 pasadena_commut, Jun 17, 2023
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  8. cyberfunk

    cyberfunk New Member

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    Thanks for those responses. At this point I'm wondering if it might be a dirty radiator. I haven't gotten the code again since clearing (4-5 startups) and I verified the pump was working several times before clearing. It was a pretty warm day with more driving than usual when the issue first appeared.

    Guess I'll clean the radiator while I'm waiting on the pump and keep driving close to home to see if I can get the code again.

    Thanks again and I'll update when its resolved or I'm stuck. :)
     
    #8 cyberfunk, Jun 18, 2023
  9. ChapmanF

    ChapmanF Senior Member

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    P0A93 can also be about the cooling fans. If I remember right, it even has a couple different INF subcodes to indicate whether the ECU thinks the problem is more likely the pump or the fans. (Just how the ECU makes that judgment, I'm not sure, but clearly somebody at Toyota thought it was worth the effort.)
     
    #9 ChapmanF, Jun 19, 2023
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  10. TMR-JWAP

    TMR-JWAP Senior Member

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    I have seen ICW pumps go intermittent, so it wouldn't surprise me a bit if the pump is in early stages of failure. It should be a basic 80k mile replacement item anyway.

    Jim Hudson Toyota in Irmo/Columbia sells them for $110ish if I remember correctly.
     
    #10 TMR-JWAP, Jun 19, 2023
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