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TPM sensors lit up for no reason

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by mwok86, Jan 13, 2011.

  1. mwok86

    mwok86 New Member

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    It's very cold here and everytime I start driving, the TPMS sensors come on randomly. I checked the PSI levels and they are all fine.

    Sometimes it comes on a cold start, sometimes when driving for 20mins.
     
  2. 32kcolors

    32kcolors Senior Member

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    Have you reset it?
     
  3. HTMLSpinnr

    HTMLSpinnr Super Moderator
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    Correct - when cold, perceived PSI is lower since the air is more dense and thus less active. If you've checked the tires with a pressure gauge, simply reset the TPMS sensors by pressing and holding the button below the steering column until the light flashes.
     
  4. adamace1

    adamace1 Senior Member

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    Yes make sure all tires are where you want them, then reset it, then when they drop something like 5psi from where you set it the tpms will turn on the light. Also do this when the tires are cold, doing it when they are warm would make the tpms system more likly to go off when it s not needed.

    I remeber another post where a few people were telling me it was normal for thiers to go off when starting their car and it always went off after driving. This would be caused by setting the tires to lets say 40psi and resetting the tpms then it would go off when the cars tires get down to 35psi. The people would check the tires and say it's just normal for the light to go off because the car says to inflate them to 32psi. But what they needed to do was to set the tires where they wanted them and reset the tpms, then when it went off the tires would be lower than they wanted them.
     
  5. LulzChicken

    LulzChicken Prius Enthusiast

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    Have you replaced any lights in the vehicle with LED's?
     
  6. Ontarget

    Ontarget Junior Member

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    I re-initialized my tpms today. I set the cold pressures at 46/40,then did the initialization. I bled off 4 psi on each tire.(42/40 now) My thoughts are that the tpms warning should come on at around 41/39. This way I can stay on top of more moderate pressure drops. I'm thinking I may re-initialize at 45/39. Is my thinking flawed? Am I missing something? Your thoughts are appreciated. Dave
     
  7. Ontarget

    Ontarget Junior Member

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    Sorry, meant to say initial was 46/44, and may re-initialize at 45/43 before bleeding off 4 psi. (I'm getting so confused)
     
  8. JimN

    JimN Let the games begin!

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    The TPMS will trip when a tire loses 25% of the set pressure. If you want it to trip at 41 you'll need to set it when there is 55 in the tires.
     
  9. adamace1

    adamace1 Senior Member

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    Why are you setting it then letting air out of your tires. You going to see the tpms warning alot by doing this.
     
  10. Tideland Prius

    Tideland Prius Moderator of the North
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    Useful if you want an earlier warning.
     
  11. Ontarget

    Ontarget Junior Member

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    I'm thinking that it will help me to keep my tires optimally pressurized. I may have to adjust them a bit more, but I don't think it will be all that much. ( maybe once every 6 weeks or so probably less as it gets warmer)