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Multiple Dashboard Lights After Hybrid Battery Replacement

Discussion in 'Gen 2 Prius Technical Discussion' started by TexasZ, Aug 14, 2022.

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  1. TexasZ

    TexasZ Junior Member

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    Four months ago, I had the hybrid batteries replaced on my Gen 2 2008 Prius - Base model with roughly 175K miles on it. Recycled batteries, not new.

    Sporadically, 4 times since then, I'll get a number of warning lights pop up that suggest something is wrong with the Hybrid charging system.

    Common conditions for the four events..
    1. It's generally hotter time of day. I live in Houston.
    2. I've been driving for a while.

    Warning lights and Codes

    On Dash (See attachment)
    1. Master warning (triangle with exclamation)
    2. Check Engine
    3. Brake System Warning (circle with exclamation in parantheses)
    4. VSC (Vehicle Stability Control)

    On Multi-Display (See attachment)
    1. Hybrid System Warning (car with exclamation)

    If I drive long enough, the AC stops cooling. When I stop the car and turn it back on, the brake system warning and VSC lights do NOT come back.

    A couple days later, all lights are gone.

    Checked the inverter coolant reservoir to make sure it was OK. It was and topped off to Max. The technician who did the hybrid battery replacement said he could see the coolant swirling in the Inverter reservoir.

    Had the codes pulled at Autozone.
    Returned P0A93 - Inverter Coolant System (See attachment).

    Since the lights have been coming on since the battery replacement, suggests something happened during the battery replacement. Could the inverter pump have failed just coincidentally? What does it look like to see coolant swirling in the reservoir with the cap off? When I look with the car running, I don't see any movement.

    Suggestions for where to go from here? Really grateful for any help! tempImageMQjNKi.png tempImageiZm0f7.png tempImagey3aar6.png
     
    #1 TexasZ, Aug 14, 2022
  2. bisco

    bisco cookie crumbler

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    look at the fluid after warm up and the engine shuts down so there's no engine vibration. if there is movement in the fluid, the pump is working.
    it's not subtle, it's obvious
     
    #2 bisco, Aug 14, 2022
    Last edited: Aug 14, 2022
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  3. Tombukt2

    Tombukt2 Senior Member

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    When I get those lights exactly like you have my cheap inverter coolant pump is gone bad I keep a few here at the ready I get out I touch the pump it's not running I am plug it plug in another one hook up the barbs hit the button immediately starts running fill up the jug let it run a minute make sure it's full full. And that's that for two or three months till that cheap pump fails. Now I fix this with another pump that looks like it's going to go the distance. So that should be not a thing for a long time now.
     
    #3 Tombukt2, Aug 14, 2022
  4. SFO

    SFO Senior Member

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    Unlikely, and ICPs don't last forever, at 175K miles when was the last time the pump was replaced?
    Personally, I've only noticed subtle coolant movement on the surface, though plenty of others have seen a rolling boil effect.
     
    #4 SFO, Aug 14, 2022
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  5. dolj

    dolj Senior Member

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    It seems cut and dry, your inverter coolant pump has failed and yes, it is most likely coincidental.
    Just a gentle shimmering moment across the top with the flow from front to back.
    This confirms the P0A93 DTC.
    Buy a new OEM pump from a good online dealer (Camelback Toyota and Olathe Toyota are a couple of good ones) You can price compare online at Toyota Part Center Online. Install the new pump and then get on with life.
    You can also put it in IG-ON mode by pressing the Start button twice without your foot on the brake so you can observe the tank without worrying whether what you see is due to engine vibrations.

    All the best.
     
    #5 dolj, Aug 15, 2022
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  6. bisco

    bisco cookie crumbler

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    thanks, i have to remember that.
     
    #6 bisco, Aug 15, 2022
  7. mr_guy_mann

    mr_guy_mann Senior Member

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    As others have noted, 90% of the time that code equals a bad inverter pump. When the power button is on (ignition on) or ready, the pump should work (minor hum, vibration, and move coolant.)

    The code means that the inverter temperature got too high. Check and replace the pump if needed, but keep in mind that the rest of the cooling system has to work properly as well. Coolant restrictions, air pockets, dirty - damaged radiator fins, or bad radiator fan can cause issues.

    Posted via the PriusChat mobile app.
     
    #7 mr_guy_mann, Aug 17, 2022
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