2012 Prius TPMS Computer Issue

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by segesvar, Dec 22, 2015.

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  1. segesvar

    segesvar Junior Member

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    We bought winter tires and wheels from a local independent tire shop in October and had them installed just before Thanksgiving. TPMS sensors were mandatory, and we wanted to have this feature in the winter too, so we paid for these (4) too. They installed EZ315MHZ, not sure of brand, sensors.

    When we took the car in, TPMS was working properly with the factory wheels, tires and sensors, and had been since we bought the car new in 2012. On installing the new set, the TPMS light was off for about 10 miles, and then came back on again. Took the car back the next day, waited while they took about an hour to finally tell her they couldn't get the sensors registered.

    Took the car back again after the holiday and had them reprogram the sensors again. After about 20 miles this time the light came back on. Took the car back again and they said they had to replace them with a different model sensor (Schrader 28365.) TPMS light was out until halfway through our 5 mile drive home.

    Next day I called and talked to the manager of the tire shop who said they couldn't get the sensors registered and I should take the car to the dealer and they'd pay for the service. Took the car in to one local dealer, and light was out when I left but it came back on the next morning. Took it back to the dealer who had mistakenly registered sensors from an adjacent car. Spent two hours while they determined they could not get the Schraders recognized.

    Took the car in to another local dealer, who had it all day and finally told me they could not get the computer to recognize the sensors. They had even tried to register it to another set of Toyota factory sensors, and the car would not recognize them. They talked with Toyota escalation and finally determined that there is either a problem with the antenna (unlikely, since it's inside the back panel, and not something easily wrecked) or the TPMS computer. Either one is $500-700 to replace.

    Since this is apparently a computer issue, I wondered why the car's TPMS "computer" (probably just a chip) could not be reflashed, since it's obviously accessible through the OBD port. After a long hold with Toyota Customer Care 1-800# today, I was told that the TPMS computer is a supplied part, not a Toyota part and even Toyota does not have the capability to reprogram them, they can only order a replacement.

    So it looks like the mopes at the original tire shop bollixed up the computer when they did the original attempt at registration, and we'll go after them for sure. But what I was wondering is if anyone else has any experience as to:

    1) Exactly where is the TPMS "computer" located?
    2) Is it a simple chip that plugs into the module somewhere?
    3) Who manufactures this for Toyota?
    4) Anyone else had this issue?

    Thanks and happy holidays,

    Rick
     
    #1 segesvar, Dec 22, 2015
  2. WilDavis

    WilDavis Senior Member

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    Welcome to PriusChat - sorry to learn of your harrowing experience, but there have been a number of recent threads discussing TPMS here on PriusChat (to some of which I've contributed, so I won't bore you with them again) - suffice it to say that my winter steelies shod with Blizzak WS-80s are now on, I'm ignoring the NagLight which goes out each time I leave the car in my garage where the summer wheels (with TPMS) are stored, and starts flashing and eventually staying "ON" after about 20 mins of driving. BTW It is my understanding that on my Gen II the TPMS system will only recognise 5 sensors! :confused:
     
    #2 WilDavis, Dec 22, 2015
  3. Mendel Leisk

    Mendel Leisk Senior Member

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    Had a memorable experience when getting snow tires (on Corolla rims) for my 2010, through a Toyota dealership. I'd made up my mind already, but still found it funny: the service writer asked I wanted sensors on the snow tires, while not-too-subtly shaking his head NO!

    In Canada TPMS is not mandatory, and I've heard in the 'States you can dodge them if you're getting tires mounted on loose rims.

    I like the idea of TPMS, just seems a shame the implementation is so difficult and expensive.
     
    #3 Mendel Leisk, Dec 22, 2015
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  4. WilDavis

    WilDavis Senior Member

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    When the dealer swapped mine, I told them not to bother with the TPMS, and they didn't question it, so I gathered it was OK.
     
    #4 WilDavis, Dec 22, 2015
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  5. segesvar

    segesvar Junior Member

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    Thanks for the two replies here; I searched through the various threads that already existed but could not find any focusing on the actual computer in the TPMS system, which is still my main concern.

    According to a sheet the tire dealer gave us, NHTSA has decreed that cars that have a working (italics mine) TPMS system must now have sensors installed. IMHO it's just one more thing to insulate drivers from the fruits of their own action (or inaction.)

    Cynic mode off.
     
    #5 segesvar, Dec 22, 2015
  6. peterjmc

    peterjmc Ping pong in Ding Dang...

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    I have an extra TPMS sensor ECU if you want to buy it. I used it to swap between winter and summer wheels. This had my winter tpms sensors registered to it. My buddy at the dealership did it for me when it came time. If i recall correctly its fairly easy to access and is in the cabin.

    LG-H811 ?
     
    #6 peterjmc, Dec 23, 2015
  7. IMkenNY

    IMkenNY Im just being nosy

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    I believe you need part # 89769-47030, approximately $40 on EBay (See link below). I think I saw it located behind the glove box.

    I modified my owners manual it now reads "Between April 1st and November 15th this light indicates that one of your tires has low tire pressure, November 16th to march 30th this light reminds you that you have improved snow & ice traction thanks to Michelin Ice tires"

    10 11 12 Prius Tire Pressure Monitor 89769 47030 | eBay
     
    #7 IMkenNY, Dec 23, 2015
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  8. phoenixgreg

    phoenixgreg Senior member

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    TPMS ECU 01.JPG TPMS ECU 02.JPG From the manual:

    TIRE PRESSURE WARNING SYSTEM PRECAUTION

    (a) When the tire pressure warning light comes on, immediately check the tire pressure of the tire and adjust it to the specified value (The tire pressure warning light will come on after blinking for 1 minute, the system may be malfunctioning. In this case, refer to following troubleshooting to repair the malfunction).

    (b) When the tire pressure warning light comes on after blinking for 1 minute, there is a malfunction in the system. Check for DTCs.

    (c) It is necessary to register the transmitter ID in the tire pressure warning ECU after replacing the tire pressure warning valve and transmitter and/or tire pressure warning ECU .

    (d) When replacing the tire pressure warning ECU:

    (1) Using the Data List, read the transmitter IDs registered in the ECU and make a note of them before removing the tire pressure warning ECU.

    (2) Register the transmitter IDs after installing a new tire pressure warning ECU.

    (e) When replacing the tire pressure warning valve and transmitter:

    (1) Take a note of the 7-digit number (transmitter ID) written on the new tire pressure warning valve and transmitter when replacing the old one. Register the transmitter IDs in the tire pressure warning ECU after replacing the tire pressure warning valve and transmitter and installing the tires and wheels on the vehicle.


    NOTICE:

    The transmitter ID is written on the tire pressure warning valve and transmitter. It will be unable to be read after installing the tire pressure warning valve and transmitter on the tire and wheel. Therefore, take a note of the transmitter ID before installing the tire pressure warning valve and transmitter.

    (f) Tire and wheel replacement or tire rotation:

    · After the tires or wheels are replaced with a new tire pressure warning valve and transmitter, it is necessary to register the transmitter IDs.

    · It is not necessary to register the transmitter IDs after tire rotation is performed.

    · After dropping the tire pressure warning valve and transmitter into the tire, disengage the bead from the wheel.

    NOTICE:

    Be careful not to damage the tire pressure warning valve and transmitter because of interference

    between the sensor and tire bead.

    · The initialization is necessary to reset the warning threshold in accordance with the variant tire pressure

    settings due to the tire types.

    (g) When replacing the tire pressure warning ECU and the tire pressure warning valve and transmitters, it is

    necessary to perform the initialization after the registration .

    (h) Precautions about the tire pressure:

    · Tire pressure decreases naturally.

    · In winter, tire pressure may decrease due to low ambient temperatures (tire pressure decreases by approximately 10 kPa (0.1 kgf/cm2, 1.5 psi) for every 10°C (50°F) drop in the ambient temperature).

    Therefore, the tire pressure warning system is more likely to indicate a warning if the tire pressures are

    not adjusted appropriately. If the daily temperature variation is large, pressurize the tires high so that the

    tire pressures are suitable under cold conditions. As a result, incorrect tire pressure warning operation

    should decrease.

    2010 Toyota Prius Repair Manual

    3. IN CASE OF TIRE AND WHEEL REPLACEMENT

    (a) When tires and wheels are replaced, always ensure that each transmitter ID is correctly registered.

    (b) Before removing the tires from the disc wheels or reinstalling the tires to the disc wheels, be sure to follow

    the correct procedures for removal and installation of the tire pressure warning valve and transmitter. Failure to

    do so may cause the tire pressure warning valve and transmitters to break .

    4. INITIALIZATION PRECAUTION

    (a) Initialize the tire pressure warning system after any of the following is performed:

    · Replacing the tire pressure warning ECU and/or the tire pressure warning valve and transmitter

    · When rotating tires on vehicles with differing front and rear tire inflation pressures

    HINT:

    The tire pressure warning system will not operate properly if it is not initialized .

    5. FAIL-SAFE FUNCTION

    (a) When a system malfunction occurs in the tire pressure warning system, the tire pressure warning light and master warning light comes on after blinking for 1 minute to informs the driver of the system failure.

    (b) The result of this diagnosis is stored in the tire pressure warning ECU.

    6. CHECK TIRE PRESSURE AFTER REPAIRS

    (a) After repairs confirm that the actual tire pressures are displayed in the Data List .

    7. REMOVAL AND INSTALLATION OF TIRE PRESSURE WARNING VALVE AND TRANSMITTER

    (a) When installing a tire, make sure that the tire pressure warning valve and transmitter does not interfere with

    the tire bead in order to prevent damage to the tire pressure warning valve and transmitter.

    (b) After completing the operation, remove the valve core to rapidly release the air in the tire and check that the

    warning light comes on. If the warning light does not come on, the system may be defective.

    (c) If there is air leakage, tighten the nut to a torque of 4.0 N*m (41 kgf*cm, 35 in.*lbf) and push the valve core

    2 or 3 times to remove any dirt attached to the valve core. If air continues to leak, replace the grommet, washer,

    and nut.

    (d) When installing the tire pressure warning valve and transmitter, make sure that the rim, grommet, washer,

    and nut are clean. Use a manufacturer-specified valve cap.

    (e) When putting air into the tire, first install the tire pressure valve straight onto the stem of the tire pressure

    warning valve and transmitter.

    8. TIRE AND WHEEL REPLACEMENT


    (a) To prevent damage to the tire pressure warning valve and transmitter, drop the tire pressure warning valve

    and transmitter into the tire whenever removing the tire from the wheel.

    NOTICE:

    Always use a new grommet, washer and nut when installing the tire pressure warning valve and transmitter.

    (b) If tires and wheels are replaced, register the transmitter IDs
     
    #8 phoenixgreg, Dec 23, 2015
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  9. Mendel Leisk

    Mendel Leisk Senior Member

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    A pdf of the above:
     

    Attached Files:

    #9 Mendel Leisk, Dec 23, 2015
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  10. segesvar

    segesvar Junior Member

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    Hello, Peter. I might be interested in the TPMS ECU you have, is it new? I'm wary of replacing it myself, but can probably get someone other than the dealer to replace it for a little less $.
     
    #10 segesvar, Dec 29, 2015
  11. peterjmc

    peterjmc Ping pong in Ding Dang...

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    Hi. It's not new, it's used. I had my mechanic at the dealership that I frequent do the swap when I switched between winter and summer wheels.
     
    #11 peterjmc, Dec 31, 2015
  12. segesvar

    segesvar Junior Member

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    Used would be OK, what's your price?
     
    #12 segesvar, Dec 31, 2015
  13. segesvar

    segesvar Junior Member

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    #13 segesvar, Jan 11, 2016
  14. Mendel Leisk

    Mendel Leisk Senior Member

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    There's a element of cargo cult in all this.
     
    #14 Mendel Leisk, Jan 11, 2016
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