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  1. yahya omar

    yahya omar Junior Member

    Joined:
    Sep 3, 2014
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    Vehicle:
    2012 Prius+ MPV
    Model:
    N/A
    Hello all
    Two days ago, the following happened to me while I was driving a Prius Plus. The high temperature signal appeared for a few seconds and then disappeared. I stopped the car on the side of the road, kept it running, and opened the front hood. I noticed a decrease in the level of coolant in the supply tank, and I noticed that the cooling fans for the radiator were stopped. I added coolant to the tank and waited for a while. For a period of time, I drove the car slowly to the house, where I reopened the hood and noticed that the fans were not working, but the engine temperature was not very high, and the coolant was also not very hot. I called a maintenance technician, and he asked me to turn on the air conditioner and see if the fans would work or not, so the fans worked. Immediately, yesterday the car was checked via OBD 2, and it showed me a code of onep118. Is it possible to check the temperature sensor without removing it, and where are the wires connected to the sensor? Are they located next to the oil gauge?
    Please advise, thank you
     
  2. rjparker

    rjparker Tu Humilde Sirviente

    Joined:
    Jun 6, 2008
    8,504
    5,066
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    Location:
    Texas Hill Country
    Vehicle:
    2012 Prius v wagon
    Model:
    Three
    P0118 is an open in the electrical circuit for the engine exhaust heat recirculation temperature sensor. It is one of two coolant temp sensors. This one is basically on a hose in the back of the engine. See pic.

    Prius gen3 exhaust Recirc coolant temp.jpeg

    It would seem there is more going on if the coolant level is dropping. Typically it is caused by a leaking head gasket on this generation. The sensor alone won’t cause a loss of coolant.

    It could also be a failing water pump, thermostat or clog caused by gasket sealer.

    I would monitor the two sensors with your scanner if it’s good enough to read both.

    Prius gen3 coolant sensors.jpeg

    This is using the “Car Scanner” app with a Bluetooth obd2 interface.
     
    Tim Jones, yahya omar and Brian1954 like this.
  3. Tim Jones

    Tim Jones Senior Member

    Joined:
    Jul 17, 2018
    1,728
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    Location:
    SE Texas
    Vehicle:
    2011 Nissan LEAF
    Model:
    ----USA----
    This doesn't sound good.... gen 3 engine not forgiving when overheated.
    Any chance fans not coming on for heater and car got hot.... driving in town... probably just wishful thinking
    ....failed water pump was replaced on mine at 169,000 i replaced it myself..... bought it at toyota dealer online low cost.
    I recommend new water pump at 150,000 especially if you go on long trips. Gen 3
     
    #3 Tim Jones, Oct 30, 2023
    Last edited: Oct 30, 2023
    yahya omar likes this.