P0171 - Where to connect my Smoke Machine

Discussion in 'Gen 3 Prius Technical Discussion' started by JanMG, Sep 28, 2025.

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  1. JanMG

    JanMG New Member

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    Hi there new to the forum. I have been trying to solve a P0171.
    I have cleaned the MAF sensor, but code is still popping up. Got my self a smoke machine to test for vacuum leaks. I just need your expert opinion where to stick this smoke machine. Nobody has a tutorial online so I hope you guys can guide me! Or point me in the right direction.

    Thanks in advance!
    Mike
     
    #1 JanMG, Sep 28, 2025
  2. Tombukt2

    Tombukt2 Senior Member

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    Green threaded tire valve lookin affair . Screw smoke fitting to that . There should be a basic tutorial and basic practice on several YouTube videos throughout the planet of car repair I'm sure . Generally those green plastic screw on connectors . Have a lot to do with.
     
    #2 Tombukt2, Sep 29, 2025
  3. JanMG

    JanMG New Member

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    Is it under the airbox? Looked everywhere for the green valve can’t find it.

    Tried to check the fuel trims. At idle it seems I am getting 0% STFT 14% LTFT. It goes to 0% STFT7% LTFT in highway speeds 110 km/h 2300~2400rpm.
    Looks like i am only running lean at low speeds. Is my assumption correct to look for a vacuum leak as i already cleaned the MAF sensor
     
    #3 JanMG, Oct 2, 2025
  4. JanMG

    JanMG New Member

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    Got it solved. It was the purge valve. All good now.
     
    #4 JanMG, Oct 10, 2025 at 12:39 AM
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