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Yellow TPMS Light should be turned on, but not?

Discussion in 'Gen 2 Prius Main Forum' started by dongfang, Apr 23, 2024.

  1. dongfang

    dongfang Junior Member

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    Hey Prius pals,

    I'm scratching my head over a TPMS light issue on my Gen 2 Prius and could use some of your wisdom. A few months ago, the yellow TPMS light turned solid on, and TechStream showed me two sensors were on the fritz. Kinda weird they both went out at the same time, right?

    So last week, I swapped out one of the bad sensors by myself (thanks to TechStream's TPMS utility), and bam, the TPMS light turned off. But I hadn't even touched the second bad sensor yet.

    I've triple-checked everything, and the car's still not picking up the second sensor, leaving us with just three working ones. And yet, the TPMS light’s stayed off, even after a TPMS reset.

    Now I'm wondering if my car's just cool with having three sensors and that the yellow light before was all about the one sensor I replaced.

    Anyone run into this before? Got any clues?
     

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    #1 dongfang, Apr 23, 2024
  2. mr_guy_mann

    mr_guy_mann Senior Member

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    No idea.

    The system may take 20-30 minutes of driving before it will realize that a sensor hasn't checked in and that it should turn the light on.

    Posted via the PriusChat mobile app.
     
    #2 mr_guy_mann, Apr 24, 2024
    wjtracy likes this.
  3. Mendel Leisk

    Mendel Leisk EGR Fanatic

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    Could be the second sensor is just on the edge of dying, some times readable, sometimes not. I had the tpms light go on last summer (with our OEM's on, with the sensors). Was on for about a week, then went out again.

    When they do go out again, I'm not going to lose any sleep. ;)
     
    #3 Mendel Leisk, Apr 24, 2024
  4. wjtracy

    wjtracy Senior Member

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    Yes per above it takes system a while 20-30min to figure out a sensor is inactive. then the light will stay on. The system reacts quickly to a valid low pressure reading, but more slowly to suss out an inactive reading. One thing you can do is insert fake codes, which temporarily puts the TPMS light out. Pushing the reset button might speed the process of updating the readings, not sure.
     
    #4 wjtracy, Apr 24, 2024
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