GEN III Prius - Smart Key Receivers in the car

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by sdupadhye, Oct 28, 2013.

  1. sdupadhye

    sdupadhye Junior Member

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    Before I elaborate my question, I want to mention that I spent quiet some Quality time with the Toyota Website Manuals as well as here on Forum. I genuinely did not find an answer. If I missed a thread, then I apologize. I will appreciate if you can point out.

    Here's my question. I am told the smart Key is NFC based by the Toyota Customer Service. (I do take anything they say with a pinch of salt.) So according to the manual, these are supposed to be located at the 4 Door handles and at the center of the car inside.

    If indeed they are NFC Tags of sorts, then I'd like to know the exact location of at least one. I want to see if I can get my Android phone to tap on the tag so that it will change its profile. On android side, I know how to handle this. Given Android implementation of NFC, I need to have physical proximity of the tag. Hence the need to know exact location. Can someone please help me with this ? TIA
     
    #1 sdupadhye, Oct 28, 2013
  2. elementnomore

    elementnomore Member

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    #2 elementnomore, Oct 28, 2013
  3. David Beale

    David Beale Senior Member

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    There is one in the rear hatch area. Easy to see and get to. Just remove the floor and storage bin. It's usually a white rectangular plastic object connected to the wiring. If the GIII is the same as the GII there is one inside the console, under the storage bin. Finally, the shop manual has drawings showing them.
     
    #3 David Beale, Oct 28, 2013
  4. sdupadhye

    sdupadhye Junior Member

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    Thanks for your response. I appreciate your time.
    That's for addition of a Smart key and a Lexus at that I believe. Although it'd be nice, to get rear hatch to work, I am not looking to do that. The wiring diagrams that OP has may not be effective for my Gen 3 Prius II.
    Thanks for responding. I appreciate the time.
    When you say console, Are you referring to the area underneath the Storage bin in the Trunk ? GIII has a Storage bin in Trunk underneath the Trunk Carpet. Presently there's spare tire under the bin. I didn't explore for what you describe but I will.
     
    #4 sdupadhye, Oct 29, 2013
  5. David Beale

    David Beale Senior Member

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    There is one in the console, the part between the two front seats, as well. The car uses them to prevent you from locking the keys in the car.
     
    #5 David Beale, Oct 29, 2013
  6. sdupadhye

    sdupadhye Junior Member

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    Thanks. That's what I read. But You need to touch the phone physically to activate the profile. So I'd like to know precise location if possible. Appreciate if you can let me know.
     
    #6 sdupadhye, Oct 29, 2013
  7. RobH

    RobH Senior Member

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    I can describe a bit about how the Gen2 SKS system works. I assume the Gen3 is similar (but it is different).

    There are a number of low frequency (about 135 KHz?) transmitters located around the car. They are located in the front doors, the console between the seats, in the the trunk, and outside the car near the rear bumper. They transmit a short message repeatedly when the car is turned OFF and looking for an unlock message. The message includes a numeric identifier of the car and the transmitter location. When a keyfob detects such a transmission, it checks to see if the car id matches the one that the keyfob has been programmed to recognize. If the car id matches, then the keyfob replies with a longer message at about 315 MHz that says something like "I heard the driver door transmitter and here's my serial number". The SKS module in the dash receives the message, and if the serial number matches one programmed into it, then the car/ignition unlock mechanism is enabled.

    The car id is programmed into the keyfob, and the keyfob serial number is programmed into the SKS module in the car.

    The encryption method used for SKS systems is not publicly documented. The encryption used on Gen2 non-SKS keyfobs is documented as KEYLOC, and is available on the web from Texas Instruments.
     
    #7 RobH, Oct 29, 2013
  8. sdupadhye

    sdupadhye Junior Member

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    Thank you very much for that detailed explanation. It helps a lot. If these are indeed transmitters sending out a message for the keyfob, then they certainly are not NFC Tags. A NFC tag acts almost similar to the RFID tag used by Department stores. That is it is passive in nature.

    So that basically shot my theory or perceived use to hell. :( Can't use it to change Android profile. I'd have to buy a real NFC tag I guess. :(
     
    #8 sdupadhye, Oct 30, 2013
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