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Gen 2 - 3 beeps 3 times after IG ON

Discussion in 'Gen 2 Prius Technical Discussion' started by Michciu94, Nov 25, 2022.

  1. Michciu94

    Michciu94 Junior Member

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    Hello

    I have keyless system and two keys. Always when I turn on IG the car make 3 beeps 3 times - so 9 beeps.

    keyless works at 2 keys without problem

    when I put first key to socket the car starts, but with second one car don’t start - but when I take it off it’s turn on normal with keyless

    I have an error code B2796. How can I repair key or try to recode etc? I think the beeps is from immo, I don’t have other fault codes (one fault for solar sensor on passenger side don’t know why).
     
    #1 Michciu94, Nov 25, 2022
  2. dolj

    dolj Senior Member

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    B2796 has the cookie text of "No Communication in Immobiliser System."

    When a key is inserted into the key slot but no communication occurs between the key and transponder key ECU, DTC B2796 is output.

    When a key is inserted into the key slot but a communication error occurs between the key and transponder key ECU, DTC B2798 is output.

    Possible trouble areas:
    • Key (door control transmitter)
    • Key slot
    • Wire harness
    • Transponder key ECU

    Hope this helps a little bit.
     
    #2 dolj, Nov 25, 2022
    PriusCamper likes this.
  3. Michciu94

    Michciu94 Junior Member

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    Yes I know :) the car transponder is ok i think becouse one key work, another key dont work so i think the key is problem - but keyless work with two Keys :D
     
    #3 Michciu94, Nov 25, 2022
  4. Michciu94

    Michciu94 Junior Member

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    And i cant erase that code - it’s always on
     
    #4 Michciu94, Nov 25, 2022
  5. mr_guy_mann

    mr_guy_mann Senior Member

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    So, a key fob has 3 "parts": the remote transmitter, the RFID chip, and the mechanical key.

    The transmitter is the part with buttons and a battery that locks and unlocks the car. It also is for the SKS system (if equipped).

    The Radio Frequency ID chip works in the dash slot as a digital key for the immobilizer system.

    And the mechanical key is for the exterior lock in the driver's door.

    What can happen is if someone gets a new shell for a fob and doesn't transfer all the bits. The RFID chip is a small plastic rectangle in the edge of the shell. If they don't know about it, it gets "left behind" and tossed out with the old shell.

    If your chip is missing or is bad, then you would need to get a new fob and program it to your car. Or you can get a used fob (ebay) and swap the chip to your fob and then program it.

    A locksmith or dealer can program the fob, or you can do it using your good fob and a capable scantool (or search "chicken dance" for a procedure that doesn't need a scantool).

    Posted via the PriusChat mobile app.
     
    #5 mr_guy_mann, Nov 26, 2022
  6. Michciu94

    Michciu94 Junior Member

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    The problem was very stupid. Those beeps was from my gas installation - remember beeps to change filters :D and the error code from immobiliser was becouse I have change case of my key fob and don’t transfer immobiliser chip - after transfer from old everything’s is working just great. I was suprised that immobiliser chip is separate from key pcb and it doesn’t have any power. Now everything is great :)
     
    #6 Michciu94, Dec 5, 2022
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