2008 Fob Issue - B2799 Engine Immobilizer Malfunction

Discussion in 'Gen 2 Prius Technical Discussion' started by tracy ing, Jun 10, 2022.

  1. tracy ing

    tracy ing Active Member

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    I have a version of techstream working, novice, and a mini vci that seems to work.

    I bought a 2008 with a stolen cat and am replacing that, when I bought the car I inserted the FOB and it was not recognized, the owner sat in car played with FOB out of the slot and leaving the FOB out of slot placed the car in ready mode, I later learned after arriving home that you must keep the FOB out of the slot in order to use the car,
    FOB SLOT LIT GREEN
    INSERT FOB STILL GREEN
    BRAKE AND POWER BUTTON, NOTHING, THE NO KEY LIGHT DOES NOT COME ON THE DASH LIKE IT DOES ON MY OTHER PRIUS WHEN I TEST IT.
    RED SECURITY DASH LIGHT FLASHES ALL THE TIME LIKE THEY DO DURING ALL OF THIS

    REMOVE FOB, PRESS BRAKE AND POWER, CAR STARTS.

    If you press the KEY button to disable that key function, the car will not start, you have to have KEY button on and the FOB near the car but not in the slot in order to start the car

    Using TS there is a code B2799 Engine Immobilizer Malfunction.

    So I am not sure where to go from here, the FOB does not have the silver logo. It is the only FOB that came with the car.
     
    #1 tracy ing, Jun 10, 2022
    Last edited: Jun 10, 2022
  2. bisco

    bisco cookie crumbler

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    perhaps the ecu is bad or corroded connections. i would advise following the service manuals trouble shooting tree
     
  3. tracy ing

    tracy ing Active Member

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    The best guess I have had so far goes like this, which would explain why it works when not in the FOB slot

    Someone had one old FOB, they bought a new fob CASE
    They removed the innards from the old fob and moved them to the new fob case, and didnt know there was a small RFID part in the old case and did not move that into the new case.

    So far, this is the only explanation that makes sense, and explains how someone got a fob to even work SKS only and not in the slot.

    Assuming this is the case, where does one go from here to fix this.
     
  4. bisco

    bisco cookie crumbler

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    you probably need a new fob from ebay andtech stream to set it up. but i would search as many threads for info as possible, there are a ton of them.
     
  5. tracy ing

    tracy ing Active Member

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    i dont think techstream will do this, and since you cant use the current sks only fob in the slot (probably doesnt have an rfid in it) you cant do the chicken dance to make an ebay fob work
     
  6. bisco

    bisco cookie crumbler

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    you might need a new ecu, i'm not sure, gen 2 and 3 are different iirc.
     
  7. mr_guy_mann

    mr_guy_mann Senior Member

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    You effectively have an "all keys lost" situation. (ie, there are no keys with a RFID chip so you cannot add any new keys to the immobilizer).

    Option 1- go to a dealer or a capable/ properly equipped locksmith and pay to have 2 new key fobs programmed (they would reset the immobilizer ecu via a "seed code").

    Option 2- DIY- you can get 2 SKS fobs and a seed code (from a questionable website somewhere in Europe once you buy some "tokens") that will allow you to use techstream and reset the immobilizer and program the fobs. You might be able to buy at least one used (sks or non-sks) fob and swap that RFID chip into your present fob then program that present fob to the car. (You can only program a used SKS fob by using a seed code).

    Option 3- U pull it- if you have LOTS of time you could find a GEN2 with SKS and grab the certification (immobilizer) ecu, WITH fobs (and maybe the hybrid control ecu while you're there). Then swap all that into your car. BUT the certification ecu lives on the firewall side of the HVAC housing- that's a huge amount of disassembly to get to it.

    Posted via the PriusChat mobile app.
     
  8. tracy ing

    tracy ing Active Member

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    lol (from a questionable website somewhere in Europe once you buy some "tokens")

    properly equipped locksmith
    YEAH THATS THE ISSUE, WHERE DO I FIND THIS GUY IN VIRGINIA MARYLAND ?
     
  9. tracy ing

    tracy ing Active Member

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  10. tracy ing

    tracy ing Active Member

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  11. tracy ing

    tracy ing Active Member

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  12. tracy ing

    tracy ing Active Member

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  13. tracy ing

    tracy ing Active Member

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  14. tracy ing

    tracy ing Active Member

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    OK, so this is kind of funny, the seller really put one over on me
    So when he started the car he left the fob out, i had tried with it in the slot, he pulled it out, pulled the fob apart, played with the battery, then started the car with the fob out.
    Then he handed me another fob in a new bag and said here is a new one it has not been programmed yet.

    So i just opened the working fob that has issues, and indeed it is missing the RFID chip, its new looking so someone took the insides and placed in a new case and didnt know about the rfid and probably tossed it in the trash

    So out of curiosity, i opened the new one to see if it had an rfid, lol it has NOTHING, the new fob that needs programming is a case only lol.
     
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  15. tracy ing

    tracy ing Active Member

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    Would this work, has nothing to do with this thread, just a question about the rfid part of the prius fob.
    If I had 5 prius cars, and each one had its own fob with rfid chip, (forget about sks thats not part of the question) and each car had only ever had ONE fob assigned to the fob slot rfid leaving room for four new fobs.

    If I took the fobs for all those cars and chicken danced them into each other. The result would be that any fob from any of the 5 cars would be able to start any of the 5 cars if placed in the fob slot ?

    I know that you cant do this for the sks part as it is a two way registration and that fob is for that cars sks,
     
  16. mr_guy_mann

    mr_guy_mann Senior Member

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    Yep, you should be able to program any Gen2 prius immobilizer to start with any Gen2 fob in the slot.

    I have had Techstream before I got my prius, so I have never done the chicken dance.

    Posted via the PriusChat mobile app.
     
  17. tracy ing

    tracy ing Active Member

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    i did it once about ten years ago on my daughters 2005 so she would have a second fob
     
  18. tracy ing

    tracy ing Active Member

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    I want to order a new fob from toyota, i have smart entry, i think my part number is 89070-47180, i also think this means that the oem fob will have a silverback logo on it, my prius is 2008

    Does this all sound right ?

    This amazon item, if the link posts, is why I am only going to toyota, this is NOT a smart fob but uses my part number, it has a black logo on the back and buyers complain they cant get it to program the sks, yeah, pretty sure its not sks, right ?

    If I am right this amazon seller is selling non sks at sks prices from the toyota dealer, plenty of dealers sell the 89070-47180 for under 130

     
  19. tracy ing

    tracy ing Active Member

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    I ordered it from a dealer an hour away, tax and mailing it to me $142.00

    Local dealer had it same price until i walked in door then it was $185.00, oh thats online price only
    Oh, so strangers you never meet get a discount, but locals that you meet and can up sell or sell a car too, they get msrp, good to know, later lol.
     
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  20. mr_guy_mann

    mr_guy_mann Senior Member

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    I guess I will never understand why people are surprised by pricing structures. Selling stuff online amazon style always costs less then having a brick and mortar location (on $$$$ real estate) with lots of flesh and blood people.

    Posted via the PriusChat mobile app.
     
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