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2019 Toyota Prius code p148F

Discussion in 'Gen 4 Prius Main Forum' started by Prabh, Oct 3, 2023.

  1. Prabh

    Prabh New Member

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    Hello everyone,

    I need some advice regarding my 2019 Toyota Prius with 180,000 miles on it. Recently, it started showing the high temperature sign. The coolant has been leaking but not on to the floor. I took it to a mechanic trouble where they ran a diagnostic test and the code P148F showed. One mechanic suggests replacing the head gasket. There's even a suggestion to replace the entire engine. I have read through some posts that say it could be Exhaust Gas Heat exchanger, but I don’t know. I'm a bit lost on what the best course of action is here. Has anyone experienced a similar issue, and can you offer some guidance on which approach might be the most cost-effective and? Your insights would be greatly appreciated.
     
    #1 Prabh, Oct 3, 2023
  2. jdenenberg

    jdenenberg EE Professor

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    Find the discussion about bypassing the Exhaust Gas Heat Exchanger. Any good mechanic should be able to do the bypass as described here on PC. As long as you haven't seriously overheated your engine all should be well.

    JeffD
     
    #2 jdenenberg, Oct 3, 2023
  3. bisco

    bisco cookie crumbler

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    it is possible that the head gasket is blown, or other damage has been done to the engine.
    but before dealing with that, have the leak fixed and refill the coolant and see how she runs. maybe you'll get lucky.
    you can replace the heat exchanger with the updated part, or just clamp on a rubber bypass.

    i am wondering though, what model year got the upgraded heat exchanger. might be a tsb on that, i'm not sure
     
    #3 bisco, Oct 3, 2023
  4. Doug McC

    Doug McC Senior Member

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    4th generation sometime in 2019.
     
    #4 Doug McC, Oct 3, 2023
  5. Doug McC

    Doug McC Senior Member

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    T-SB-0135-19
     
    #5 Doug McC, Oct 3, 2023
  6. BiomedO1

    BiomedO1 Senior Member

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    Welcome!!
    1. test for coolant leak - should be positive test.
    2. loop out the Exhaust gas heat exchanger, then retest. If the test is now negative - you've got your answer.

    Alternatively, you can just loop-out the exhaust gas heat exchanger, and keep checking the coolant reservoir for the next month. If you stop losing coolant, there's your answer.

    Hope this helps.....

    PS. I'm assuming the P148F code and the intermittent high temp warnings was caused by low coolant levels.
     
    #6 BiomedO1, Oct 3, 2023
    Brian1954 likes this.
  7. Drakxyfly

    Drakxyfly Junior Member

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    #7 Drakxyfly, Oct 9, 2023
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