TPMS light confusion

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by splitter, May 27, 2026 at 7:26 PM.

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  1. splitter

    splitter Junior Member

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    Hi everyone!

    I have a confusion about the TPMS light.

    Two TPMS sensors have gone on my wife's 2006 Prius - the TPMS light flashed on start then eventually settled on solid.

    I bought 4 Denso "OEM fit" sensors from RockAuto hoping to save a bit of money (DENSO 5500103) and have booked in at a local shop to have them fitted. They seemed a little confused about whether they would need to "program" them or not (they are pre-programmed I believe).

    To save some time and confusion, I decided to add the new sensor IDs to the car via TechStream before the new sensors are fitted.

    After doing this, the TPMS light has turned off. The sensors are still in the box, not installed. I drove round for 15 or so minutes, and the light did not come back on.

    I'm very confused about this. I would have thought that with the new sensor IDs on the car, the TPMS light would again be on since they can't be showing any pressure.

    Have I misunderstood something about this procedure?

    Bonus question: Anyone familiar with whether these particular sensors need to be "activated", e.g. tpms tool trigger, rapid deflate/inflate cycle?
     
    #1 splitter, May 27, 2026 at 7:26 PM
  2. JC91006

    JC91006 Senior Member

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    If you put in new sensor codes, you can confuse the computer for about half an hour, if your drive exceeds that, your light will come back on
     
    #2 JC91006, May 27, 2026 at 7:41 PM
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  3. rjparker

    rjparker Tu Humilde Sirviente

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    They don't need to be activated. They have motion detectors to turn them on.
     
    #3 rjparker, May 27, 2026 at 11:35 PM
  4. Mendel Leisk

    Mendel Leisk MMX GEN III

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    The car needs to be programmed to recognize the new sensors, hopefully possible with what you’ve got. Both prepurchasing the sensors and the “confused” shop does not bode well. It’d be preferable to go with a shop that’ll do “turnkey”, knows their stuff and supplies/guarantees the sensors.
     
    #4 Mendel Leisk, May 28, 2026 at 8:57 AM
  5. splitter

    splitter Junior Member

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    My understanding with the "OEM" Denso sensors is that they don't need to be programmed. Instead, you just need to install and activate them (or maybe not...) and then add their IDs to the TPMS ECU via TechStream. I can do the latter step. I need the shop to install them (and possible activate them).

    On a related note, I drove around for nearly 40 minutes this morning and the TPMS light has still not come back on. I also turned the car off / on multiple times to try to force a reset. I find this very confusing. The IDs saved in the car's ECU are the new sensor IDs which are still in the box on the passenger seat. So the TPMS light should be on. Either it takes forever for the car to recheck the sensors, or I've stumbled across a way to disable the TPMS light, perhaps along the lines of this thread: Techstream and TPMS - ClubLexus - Lexus Forum Discussion
     
    #5 splitter, May 28, 2026 at 9:02 AM
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  6. JC91006

    JC91006 Senior Member

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    I've had this same feeling when I changed the sensor ID. Trust me, it'll come back on. If it were only that easy to disable a TPMS light, we would forget about using sensors altogether
     
    #6 JC91006, May 28, 2026 at 10:09 AM
  7. PrimalPrius

    PrimalPrius Member

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    A fairly easy DIY. Tighten a 2" cargo strap around the perimeter of the tire, set some 2x lumber on the floor so that it touches the tire but not the rim and jump on the rim to break the bead. Use a fishing line or string when removing the old sensor and installing the new one. A tool like this makes that step easier: More Information for PERFORMANCE TOOL 60501.
    To reseat the bead just adding air often works for me. Remove valve stem before air if tire won't seat with the valve stem in place.
    Edit: If there is a big weight difference between previous and new sensor and old, it could have an effect on tire balance that can be noticed.
     
    #7 PrimalPrius, May 28, 2026 at 12:10 PM
    Last edited: May 28, 2026 at 3:22 PM
  8. rjparker

    rjparker Tu Humilde Sirviente

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    Most likely the id programming in the car's ecu is done (as you indicated much earlier), the sensor motion detectors turn them on (activate not the proper word) and "possibly" you set the tpms alarm point at zero.

    prius tpms 2023-09-18.jpeg


     
    #8 rjparker, May 28, 2026 at 1:07 PM
    Last edited: May 28, 2026 at 4:17 PM
  9. splitter

    splitter Junior Member

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    Thanks, this is useful!

    Just in case, I reset the TPMS by jumpering 4 and 13 on the OBDII port for 30 seconds (diag mode appeared on MFD). I then re-registered the new sensor IDs. I drove around for a while but still no TPMS light - maybe it will just take a while to pop up.

    I've attached a screenshot of the TPMS data after the reset and re-registration.

    I'm booked in to get the sensors installed tomorrow. I was hoping to have the TPMS light present so it going off would indicate all sensors have been "turned on". I think I'll go ahead with the install, and then have to check afterwards whether the ECU is communicating with them.
     

    Attached Files:

    #9 splitter, May 28, 2026 at 4:07 PM
  10. rjparker

    rjparker Tu Humilde Sirviente

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    TPMS alarm initiation is normally done with the switch under the drivers dash. See owners manual.

    Take a picture of the ids before install, have them installed and then drive about 5 minutes or less.

    The id on this one is
    5528CA0 IMG_1556.jpeg
     
    #10 rjparker, May 28, 2026 at 4:24 PM
  11. ChapmanF

    ChapmanF Senior Member

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    Caution for anyone looking at the photo in #8 and thinking "Oh! So ID1 is rear passenger, ID2 is rear driver side, and so on!"

    Nope! The IDs don't go with particular corners. They're just four arbitrary slots to register your transmitter IDs in. You can make notes like in that photo to remember which one you put in which corner, but if you do, you have to remember to update the notes (correctly!) each time you rotate the tires.

    Also, if you have work done at a tire shop, they'll often use a tool that reads all the transmitter IDs and programs the car's ECU with them. They might do it for convenience without you asking. It can result in you having the exact same 4 transmitter IDs registered that you came in with, but not in the same numbered ID slots, so your notes will be thrown off again.
     
    #11 ChapmanF, May 28, 2026 at 4:57 PM
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