AC Freeze Issue

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by TwoPriusInTenn, Jul 5, 2025 at 12:42 PM.

  1. TwoPriusInTenn

    TwoPriusInTenn Member

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    2008 -: AC works great and blows cool. After a while the coolant line near the compressor appears tofreeze up and no longer blows cool. Refrigerant level looks good. Also just replaced the thermistor. Anything else I should check?
     
    #1 TwoPriusInTenn, Jul 5, 2025 at 12:42 PM
  2. ChapmanF

    ChapmanF Senior Member

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    Which thermistor did you replace?
     
    #2 ChapmanF, Jul 5, 2025 at 1:00 PM
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  3. TwoPriusInTenn

    TwoPriusInTenn Member

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    The outdoor ambient temp sensor (thermistor) in front of the radiator.
     
    #3 TwoPriusInTenn, Jul 5, 2025 at 5:42 PM
  4. mr_guy_mann

    mr_guy_mann Senior Member

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    Does the airflow from the dash vents change when it stops cooling? What you describe sounds like evaporator freeze-up. The system gets too cold and the water vapor that condenses turns to ice.

    There is a temperature sensor that (should) read how cold the evaporator gets, and the ecu should use that to control the compressor to prevent freezing. I would want to use a capable scantool & read that temperature sensor - is it accurate, and what does it show when there's a problem?

    A guess would be that someone did work (like replacing the evaporator) and didn't refit the temperature sensor into the evaporator fins.

    Posted via the PriusChat mobile app.
     
    #4 mr_guy_mann, Jul 5, 2025 at 8:37 PM
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