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Low Tire Pressure Idiot Light Came On...

Discussion in 'Gen 3 Prius Main Forum' started by Vege-Taco, Jul 31, 2012.

  1. Vege-Taco

    Vege-Taco Junior Member

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    This morning my TPM light came on. I stopped off at a service station and checked all the pressures, but they were all fine. Is there is history of faulty sensors?
     
  2. Paradox

    Paradox Prius Enthusiast / Moderator
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    When did it come on? Is there a possibility you stopped and pressed hard on the brake and activated the hill start assist and just thought the HSA light was the TPMS light?

    Did the light stay on until you went to add air, did it go off right away or is it still even on?
     
  3. Vege-Taco

    Vege-Taco Junior Member

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    The light looks like this: [​IMG]

    What does the hill start light look like?
     
  4. Vege-Taco

    Vege-Taco Junior Member

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    The light came on in my driveway when I started the car this morning. It was on after I checked the tire pressures, which were fine at 35 rear, 38 front. It stayed on all the way to work 17 miles.
     
  5. Paradox

    Paradox Prius Enthusiast / Moderator
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    Goggle did not return me a result with a pic of the light but that is the TPMS light so its not the HSA.
     
  6. Paradox

    Paradox Prius Enthusiast / Moderator
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    do not know, I was thinking maybe the pressures went up once the car was driven and one may have been low but it stayed on the entire time, even after seeing the pressure was good in each tire. I don't immediately remember seeing people with sensor problems, but anything is of course possible.
     
  7. Quattro

    Quattro Member

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    The system compares a baseline number with the current pressure and flags if the difference exceeds a certain limit. You can reset the TPMS by pressing a button under the dash & whatever pressure the tires are at becomes the baseline. Maybe the system was set at hot temp and dropped below the limit when the car was cold in the morning. You can try reset it in the morning & see if it happens again.
     
  8. Mike500

    Mike500 Senior Member

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    It could be battery failure in the TPMS sensor inside the tire.
     
  9. rogerv

    rogerv Senior Member

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    It's a bit more complicated than just pressing the button; check the manual for the procedure.
     
  10. car compulsive

    car compulsive Active Member

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    I have aftermarket sensors in my summer wheels/tires and one of them is starting to act up. The indicator is never lit when I'm near the Belle Tire store, though.
     
  11. retired4999

    retired4999 Prius driver since 2005

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    In most cars the spare also has a TPMS, check that too maybe. just a wild guess.
     
  12. ursle

    ursle Gas miser

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    I'd let the dealer know, just make sure it get's on the toyota computer, if you do have a sensor problem it'll already indicated, might make it easier down the road. I like the check the spare idea but doubt it, must just be another digital electrical gremlin, if after 7 or 8 restarts it's still there it's a problem... I'd be tempted to unhook the 12v for a reboot of the system but before doing that, if it's there in the am the dealers OBD11 reader will be free and thorough.
     
  13. fatfingers

    fatfingers Junior Member

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    Check the spare, did you have the tires changed lately? More often than not the sensors get cracked when removing/installing tires, the sensor is right under the valvestem. Aftermarket tire shops will kill far more sensors then are found defective.
     
  14. mrtremere

    mrtremere Junior Member

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    As a Jeep Wrangler Owner TPMS is the biggest pain in the nice person.
    First thing we do is spend $100 on a tool that can disable the sensor.
    Technology we did not need.
     
  15. rogerv

    rogerv Senior Member

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    I took an elderly friend's nine-year-old Cadillac to the dealer for service a few months ago, and one of the problems was one or two of the sensor batteries were weak. They worked when on the rear of the car, near the receiver located in the trunk, but failed after the tires were rotated. The tech said they are meant to last only about five years, so these were on borrowed time. You can't replace the batteries, but have to buy new sensors for $125 each, and then pay for labor to replace them, balance the tires, etc. We decided to ignore the messages and check the tire pressure the old-fashioned way. The car has since been donated to a charity.
     
  16. WE0H

    WE0H Senior Member

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    How long do the batteries last in the Toyota sensors?

    Mike
     
  17. priuscritter

    priuscritter I am the Stig.

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    Don't do anything with it. Take it the dealer as you have a 2012 and I assume it's under warranty. A faulty sensor is my bet.
     
  18. Munpot42

    Munpot42 Senior Member

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    I'm a new fan of the tpms in Toyotas. The sensor lit up a couple of days ago, all the tires looked ok, but I took out my trusty tire gauge and the pressures read 32, 34, 34 and 15. Inspected to 15 tire and found a lovely nail right in the middle of the tread. Pumped up the 15 to 32, drove to the tire shop, had the tire fixed and I'm on my way. The shop balanced all the tires to the recommended 33psi. Beats driving on that low tire till I ruined it! .
     
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  19. CR94

    CR94 Senior Member

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    Who recommended 33?
     
  20. fuzzy1

    fuzzy1 Senior Member

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    Note that he has some 'Other Hybrid', not a Prius, so don't go by the Prius recommended numbers you remember.
     
    #20 fuzzy1, Dec 16, 2017
    Last edited: Dec 16, 2017
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