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Prius reading P0125 after full etc and thermostat replacement

Discussion in 'Gen 2 Prius Technical Discussion' started by Rose Sonnenberg, Jun 2, 2021.

  1. Rose Sonnenberg

    Rose Sonnenberg New Member

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    Hello. I just replaced the sensor and thermostat after getting a P0125 code. The thermostat was stuck open so figure to replace sensor with it as well.
    A little background. I idle my car in the morning while I get ready for work, to heat up my block for driving. About 30 mins. Ac on. To heat up/ cool down my car before I get in.
    This morning I did this and check engine came up. Carista says P0125 even though coolant is full and thermostat is fine. Just a little while ago my dad hooked it up to see the running temp. Hangs in the high 170- 189 drops when it gets to 189 back into the 170 range. Thermostat is operational. What could the issue be? Should I clear the code and hope it doesn’t come back. Could there be a bad wire somewhere? If anyone has had this issue please let me know. I’m getting a new etc sensor in case the one I put on was faulty.
     
    #1 Rose Sonnenberg, Jun 2, 2021
    Last edited: Jun 2, 2021
  2. PriusCamper

    PriusCamper Senior Member

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    Yes clear the code and see how long it takes to return. Also only really old cars needed to be "warmed up." Prius and most all newer cars are designed to simply start up and drive them. No need to waste gas and pollute the atmosphere doing a warm up. Not necessary these days.
     
  3. SFO

    SFO Senior Member

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    If not OEM from the dealership, which brand and part # were they replaced with?

    Here is the step by step workup for DTC P0125 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/2054m/cip0125a.pdf

    FYI - your posts are being moderated until you've posted five times.
     
  4. Rose Sonnenberg

    Rose Sonnenberg New Member

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    2007 Prius
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    One
    Ah I see. I’m used to driving an old Volkswagen which needed to be warmed habitually. Upon further digging it seems that allowing the car to idle can cause this code. I will clear it and not idle it in the morning from now on and see if that helps.
     
    donbright and PriusCamper like this.
  5. Rose Sonnenberg

    Rose Sonnenberg New Member

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    One
    Also self explanatory but I meant ECT not etc. autocorrect.
     
    PriusCamper likes this.