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SKS (Smart Key) Trouble; Hybrid Immobilizer Light

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by cwoodr91, Oct 7, 2017.

  1. cwoodr91

    cwoodr91 Junior Member

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    Hi there,

    Problem:
    I have the SKS in my 2007 Prius. Neither the master nor the spare key works anymore. Both proximity functions and buttons are all dysfunctional. HOWEVER, the hybrid immobilizer light (red car-shaped icon with shape of key in middle) still flashes when I get into the car with EITHER key, which suggests that the sensor still registers the presence of both keys.

    Question:
    Does the indicator light imply I can revive the keys somehow? If so, any thoughts?

    What I've Tried:
    -Replaced batteries in both keys (fresh as of this morning) - no dice
    -Cycled the SKS system using the "key" button under the steering wheel
    -Tried re-programming the master key (both trying to "confirm" it as the existing master, and to "add" it as a new key)

    ...and I have been careful to keep the two keys separated while testing any of this.

    Other Notes:
    -The master key was missing for about 7 years, but has now been found. It is still in perfect shape. It worked initially after being found, and has since stopped working.
    -The spare key has gone through the wash. It HAS worked sporadically since then, but has now stopped working.
    -Other threads have mentioned the 12v battery. Water was getting into the 12v battery well a few years ago. I traced the leak, patched it, and I have not had any problems since. (I found out about the water because it screwed up the ABS system, which produced the red triangle of death.) The keys HAVE worked since this occurred.

    I desperately want to avoid paying a dealership for re-programming (quoted at $135) or, worse, a new key (quoted at $229 + tax + $135 for initial program). I suppose I would pay for a new master through a third party and program it myself if I was confident that would work. But I'm hopeful I won't have to do any of that, given the indicator light on the dashboard.

    Forgive the essay. Thanks for any and all input.
     
    #1 cwoodr91, Oct 7, 2017
    Last edited: Oct 7, 2017
  2. bisco

    bisco cookie crumbler

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    how is the 12v health?
     
  3. cwoodr91

    cwoodr91 Junior Member

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    12.3v in ACC mode, down to 11.9-12v with system on, up to 14.1-14.4v with car running.
     
  4. bisco

    bisco cookie crumbler

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    doesn't seem too bad, but not sure how much draw accessory mode applies.
     
  5. cwoodr91

    cwoodr91 Junior Member

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    I may have had that replaced after the incident I describe above. Can't remember. At any rate, what I've read suggests that it's well within the healthy range.

    So it's not the battery in the key, it's not the 12v in the car, and it's not the key switch under the steering wheel.

    One thing I forgot - when re-programming the keys, the car is supposed to indicate either that it recognizes the master or does not. Above, when I say that re-programming did not work, I mean that the car indicated it did not recognize the master. Perhaps a helpful tidbit. Maybe some light separation anxiety?
     
  6. cwoodr91

    cwoodr91 Junior Member

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    Reading here: SKS issue | PriusChat

    It looks like this person found success in replacing the door lock receiver. I feel I'm about to go down this rabbit hole. I'll report back!
     
  7. cwoodr91

    cwoodr91 Junior Member

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    I replaced the door lock receiver for $10... to no avail.

    I started from scratch and replaced both fob batteries again. For some strange reason, this fixed the spare... but not the master.

    Tried the chicken dance again now that I have a working key. Still no luck with the master.

    Getting dangerously close to having to pay somebody else. :sick:

    Any other ideas out there??
     
  8. exstudent

    exstudent Senior Member

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    THIS IS ALL YOU HAD TO STATE, especially text highlighted in blue.

    Something caused the SKS function to stop working correctly, as observed with the re-found "master" and machine washed FOB. What was this event, if you can recall? This is the source of your problems. The 12V and FOB battery were strong enough, for the SKS to function correctly, prior to the mysterious event. Was your car in an accident? Was you car in a flood?

    EDUCATION TIME:
    Gen1 (1997-2003) uses a MASTER key and uses a MASTER designation for programing additional keys.
    Gen2 (2004-2009) Prius does not have, or use, a Master/Slave FOB designation.
    As long as you have a 100% functioning Gen2 FOB (all functions work), you can program a 100% new, virgin, FOB for Gen2 by yourself.

    Read the SKS section in your Owners Manual; it explains it OK, not well.

    SKS Prius has "Oscilators" (think antenna) looking for correct KEY ID and VEHICLE ID transmitted by SKS fob:
    Exterior oscilators- front doors (Right and Left), rear hatch,
    Interior oscilators: center console (covers front), left rear quarter panel (covers rear)​

    Each SKS fob has a KEY ID and VEHICLE ID, "burnred" onto the SKS fob motherboard by the vehicle's CERTIFICATION ECU (brains of SKS).
    • The SKS fob transmits these two pieces of info with a working fob battery. When in range of your SKS Prius, you will be able to enter and start your vehicle without ever reaching for your SKS fob.
    • KEY ID and VEHICLE ID are unique to your SKS Prius, and created by the CERTIFICATION ECU, which was set at the factory.
    • This is why 100% new, virgin SKS fobs are required to have 100% SKS functionality.
    • When a used SKS fob is attempted to mate to an SKS car, the used SKS fob will only be able to function as a dumb fob (manually insert into fob slot every time). The used SKS fob already has a KEY ID and VEHICLE ID "burned" onto the SKS motherboard, that is not recognized/authorized by the Prius to work in SKS mode. Defeats purpose and convenience of SKS.
    • 100% new, virgin SKS fobs are a little bit more than used SKS fobs on crapBay(eBay) and Amazon.
    • When all original or the last working SKS Fob is lost, dealer intervention is required. A pricey rest (clear all authorized fobs from memory) and reseed (add fobs) will need to be done.
    • Supposedly, used SKS fob can be made to function correctly, but requires dealer intervention (reset/reseed). Given the cost of dealer labor, and the small cost difference of new vs used SKS fob, new SKS fob is the way to go.
    • A used SKS fob can work correctly on a non-SKS Prius, for obvious reasons; no SKS in the car.
    • Maximum number of Fob (SKS or non-SKS) a Gen2 Prius can be programed with is 4, IIRC (if I recall correctly). Two spots are occupied by the original two Fobs that came with the new car. There are only 2 more slots left.
    END OF CLASS.


    1) You CAN NOT program/reprogram your current SKS Fobs, b/c they are already programmed to your car.
    2) In post #7, you state
    BE SPECIFIC. Your descriptions are vague, and do not help with diagnosis.
    Is the spare SKS fob the long lost "refound" SKS fob or the machine washed SKS fob?
    What do you mean by fixed?
    Is every function of the SKS Fob working?
    SKS functions works completely: lock/unlock via small black button on both exterior door handles.
    Trunk can be opened via small black button on trunk.
    Able to Start the car via SKS, w/o ever inserting SKS Fob into dash FOB slot.
    With SKS dash button depressed to deactivate SKS, able to start the car with SKS Fob in dash slot?
    Remote buttons on SKS Fob works completely:
    lock all doors,
    unlock drivers door (1-time unlock tap),
    unlock remaining doors (2nd unlock tap),
    alarm button​
    3) Since SKS Fobs have a motherboard inside, it could be possible for the motherboard to go bad, completely or partially. This could account for one SKS Fob (assumed) working, and the other not working.
    4) It could even be an ECU issue for the entire SKS system. Maybe an ECU or two is bad. Maybe an ECU is experiencing intermittent operability? Hope the latter is not the case.
    5) You will likely have to get dealer service to do a reset/ressed.
    *You have their labor cost of $135. Ask for a discount: student, military, fire, police, student, AAA/Costco/AmEx member, etc.
    *Buy two 100% new, virgin, SKS Fobs from Camelback Toyota; Don't know if both are SKS, or maybe 1 is a retired SKS part #, or the cheaper price might be non-SKS fob.
    Fob part number: 89994-47061 is $156.07
    Fob part number: 89904-47011 is $131.69
    Camelback Toyota Webiste: 2007 Toyota Prius Parts - Camelback Toyota Parts - Genuine OEM Parts - Free Shipping
    Free shipping on $150+. Likely to still have no sales tax, unless shipped w/in Arizona.​
     
    #8 exstudent, Oct 15, 2017
    Last edited: Oct 15, 2017
    broski, cwoodr91 and SFO like this.
  9. cwoodr91

    cwoodr91 Junior Member

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    Hugely helpful, thank you.

    Seems I'm damned if I do and damned if I don't in these forums. Some complain about too much info, some too little. I don't know exactly what's relevant to the problem, hence my post!

    In 2012, the car was rear-ended, hard enough to create a tiny crack in the frame near the right-side hatchback arm, which allowed in rainwater, which conveniently collected in the well around the 12v battery. HOWEVER, I patched the crack, drained the fluid, and replaced the battery, all in 2014 (when I first noticed the water, which was slow to collect into a problematic enough size). The SKS has worked since then. Unless some latent effect from this could have caused the more recent malfunction, I do not know of a mysterious event, unfortunately. All that said, I assume this is now irrelevant since I have one working fob (more details to follow).

    This is great news, as it is the machine-washed (non)slave that is now my one working fob.

    Your point #2...
    In my initial post, I answer this question: "The spare key has gone through the wash." Albeit, I now know that it is irrelevant which is the spare and which is the master.

    Yes.

    ---

    Your point #3... This sounds like the most plausible cause, because...

    Your point #4... ...the system has been working entirely properly and consistently with the one fob for over a week now. Time will tell.

    Your point #5... I have ordered one virgin fob which I intend to program using my one working fob. If that fails, I'll bite the bullet and visit a dealer. Thanks for the details about available discounts.

    Lastly, I swapped the guts out of the working-but-battered fob into the non-working-but-nice-looking fob, so at least I get the best of both worlds there. :)
     
  10. dolj

    dolj Senior Member

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    Make sure the "guts" includes the RFID chip that resides at the front of the bottom half of the fob. It is a dark coloured rectangular shaped what looks like plastic with one of the corners cut off. Make sure your testing includes starting with the fob in the key slot, which confirms the RFID chip is working.
     
  11. DashingDave

    DashingDave Junior Member

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    OK, Now I have a strange question: Why / What is the "RFID chip that resides at the front of the bottom half of the fob" ?

    My 2006 Prius Key FOB does NOT have this small piece - only a printed circuit board.
    Yet the Prius remotely opens the doors as I approach and the Car starts (usually).

    So if that piece is vital - why is my Key FOB working without it ?
     
  12. dolj

    dolj Senior Member

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    The other two systems you mentioned run off the PCB so as you have observed, as long as there is a working CR2032 battery installed they work just fine.
    The RFID is there as a failsafe in the event your fob battery goes flat. It runs off inductive power, just like contactless credit and transit cards do.

    What this means is if your fob battery goes flat, you can open the car with the mechanical key, insert the fob into the key slot and start the car.

    With the RFID chip missing from your fob, you do not have this failsafe, so your car will not start with the fob in the slot. So, you better make sure you can always have or get access to a new CR2032 button battery.
     
  13. DashingDave

    DashingDave Junior Member

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    Thanks, that clarifies it beautifully.
    So the RFID is a backup to the "motherboard" PCB in the FOB.

    The guy trying to sell me his $420 key solution insisted that the RFID portion was essential.
    But then he was speaking Mexican Spanish - which is not my forte.
    Nevertheless, I think i understood him well enough.
    But he didn't want to understand when I showed him the dash lights
    would recognize the key when it was close - and not when it was out of the slot.

    Since my Key FOB never had that RFID piece, can I buy it separately ?
    Or does it need to be Keyed to my Car (ECU, VIN etc.) ?

    Anyway, thanks for clarifying.

    PS Hey, I see you are in Wellington, I just drove 5,000 ks on your South Island.
    Spectacular. Even had a thrilling swim with Dolphins. Sorry I didn't get to see
    your fair ville. Three Cheers.
     
  14. dolj

    dolj Senior Member

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    I guess if you are trying to pair it to the car, it is essential for it to be present. I don't know if it prevents setting up the remote lock/unlock and SKS, though.
    No worries.
    Yes, Te Wai Pounamu (the South Island) is spectacular and well worth seeing. I think you got the better deal if scenery is what you were after. Te Ika a Maui (the North Island) is quite different and more populated. I'm glad you enjoyed your time here.