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Dashboard Ignition

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by 2005with259k, Apr 27, 2022.

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  1. 2005with259k

    2005with259k Junior Member

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    ----USA----
    Really weird dash question. My car does not start or go in ready mode once the FOB is in the dash ”ignition slot”. I checked the button under the steering wheel. If it is in the “key needed” position where you have to put the FOB in the dash the car will not start at all. Whether I put the key in the dash “ignition slot” or not the car will not start. If I push the button under the steering wheel so that I can start it with the FOB Smart Key function and not in the “ignition slot” it starts right up and recognizes the key is in the car until I put the key FOB into the dash. Once it is stuck into the dash, the car no longer recognizes the FOB is in the car. It is not the FOB. That I replaced first thinking it was the problem but nope same. I have to have the FOB outside the dash to stat car. Once started it can be anywhere as you know because it will stay running. Just the opposite of what you would expect to happen.
     
    #1 2005with259k, Apr 27, 2022
  2. ChapmanF

    ChapmanF Senior Member

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    Was this fob ever "re-housed" in a new case? Sometimes people wear out the plastic case and buy a replacement online, and just move the insides of the fob to the new case.

    There are two things inside that need to move over. There's the big obvious printed circuit board, where all the wireless functions are. There's also a tiny little wedge-shaped black chip that holds the RFID code needed when the key is in the slot. If somebody overlooks that chip and leaves it in the old case, this happens.

    If that's not what happened ... are there any warning lights or trouble codes? I might suspect the wiring between the slot's transducer coil and the ECU it connects to.
     
    #2 ChapmanF, Apr 27, 2022
    2005with259k likes this.
  3. mr_guy_mann

    mr_guy_mann Senior Member

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    The fob has three "parts" - 1) the remote keyless access or SKS if equipped (that's the battery operated part with the buttons), 2) the immobilizer (a little RFID chip in the fob case or shell that works in the dash slot), and 3) the mechanical key for the driver's lock cylinder.

    It sounds like something is wrong with the immobilizer system. Could be the RFID chip is missing or not programmed into the car's ecu. Could be a fault with the receiver slot in the dash. Do you still have the old fob? Did you transfer the RFID chip from the old fob to the new one? Or how did you program the new fob? Do you know if you ever had a fob that worked correctly in the dash slot?

    You may need to use a capable scantool (such as Techstream) to see if the transponder ecu has any codes.

    Posted via the PriusChat mobile app.
     
    #3 mr_guy_mann, Apr 27, 2022
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  4. 2005with259k

    2005with259k Junior Member

    Joined:
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    Vehicle:
    2005 Prius
    Model:
    ----USA----

    You know what gentleman you are probably both right! I bought the car used with one FOB and I had to replace my FOB because I dropped it too many times on concrete. The chip is probably damaged. Thanks so much!
     
    #4 2005with259k, Apr 27, 2022
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