tire pressure light on after new tpms sensors

Discussion in 'Gen 2 Prius Technical Discussion' started by toy4speed, Apr 18, 2018.

  1. toy4speed

    toy4speed Junior Member

    Apr 18, 2018
    Fremont, CA
    2007 Prius
    Been living with the tire pressure warning light on for the past year, on my 2007 Prius. Tires pressures have always checked fine, so assumed it was one of the tpms sensors maybe getting old, or battery dying. So, 2 weeks ago I installed 4 new tpms sensors (by VDO), then initialized the 4 sensors to the car's ecu with a ATEQ TPM Quickset tool. Stored the ID#s of each sensor into the ATEQ, then hooked it up to the OBD2 port on the car, and amazingly the tire pressure warning light went off. The ATEQ worked exactly as described. Happy for about 2 weeks, then went on a 2 hr drive last weekend, the dreaded light came on. When I got home, I initialized the sensors into the car again, and light went off again. 3 days later the light came on, and now the ATEQ seems to have trouble resetting the ecu. No window film on the car, wondering if something else in the car could be acting up? Any thoughts?
  2. wjtracy

    wjtracy Senior Member

    Sep 19, 2006
    Northern VA (NoVA)
    2006 Prius
    Could be a mistake in code numbers, maybe re-enter.

    When you put in new codes, you can even put garbage in there like 0000000, that action will turn off the warning lights temporarily.
    It takes a longer drive about ~30 minutes for the system to realize that it is not getting real data from the assigned TPMS codes. If you only ever take short 10-minute trips, you can go weeks or months before you take a long enough trip for the system to realize it is not getting valid new data, and then finally the warning light comes on/

    So basically it sounds like there is a problem with one or more TPMS or the codes... the fact you can turn out the light temporarily by inserting new codes is just the way it works. I think if you hit the RESET button that would probably speed up the process of forcing the system to look at the pressure readings and give an error if there is no reading.

    I use the Techstream which allows seeing the tire pressure/temp readings and you can debug what is happening by letting out some air on each tire and watch the readings change.
    #2 wjtracy, Apr 19, 2018
    Last edited: Apr 19, 2018
  3. dolj

    dolj Senior Member

    May 14, 2012
    Wellington, New Zealand
    2006 Prius
    You never said whether you set the tires to the correct pressure and reset the system. Perhaps the tires are under-inflated, due to a slow leak?