able to drive prius without key in dash-- and i don't have a smart key system!

Discussion in 'Gen 2 Prius Main Forum' started by fortheanimals, Dec 19, 2011.

  1. fortheanimals

    fortheanimals Junior Member

    Joined:
    Aug 15, 2005
    87
    0
    0
    Location:
    portland, or
    Vehicle:
    2005 Prius
    Model:
    N/A
    i recently made a curious discovery about my prius after 6+ years and 80k miles. i usually start the car with both hands. i'll use one hand to push start while simultaneously sticking the fob in with the other (i often misfire on timing). the other morning, i hastily jammed the fob in while pushing start, but the fob was spit back out by the springs. the car still went into ready mode! i reluctantly started driving, afraid some computer malfunction would leave me stranded on the road. everything was fine as i drove slack-jawed for the next 5 minutes or so. the next day, i tried to recreate this wonder, and all it took was a little finesse and manipulation to get the fob to trick the car without locking in. somehow, the car feels lighter and more zippy when i drive fobless!
     
  2. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
    Staff Member

    Joined:
    May 11, 2004
    14,810
    2,468
    65
    Location:
    Far-North Chicagoland
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    Interesting. To my knowledge, no one has ever played around with inserting the fob enough to start the car but not lock it in.
     
  3. fortheanimals

    fortheanimals Junior Member

    Joined:
    Aug 15, 2005
    87
    0
    0
    Location:
    portland, or
    Vehicle:
    2005 Prius
    Model:
    N/A
    phew! so glad i didn't do a poor search of this subject to make sure i wasn't being redundant. i've been on these boards off and on since i got the prius, and i was pretty sure this would've made a more noticeable splash if discovered. do i win a prize?
     
  4. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,037
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    The fob uses RFID, which requires it to be near the slot. It does not make electrical contact inside the slot.

    Tom
     
  5. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

    Joined:
    Apr 13, 2004
    15,140
    610
    0
    Location:
    South Puget Sound, WA
    Vehicle:
    2013 Nissan LEAF
    Model:
    Persona
    so this means after you start you can pull the FOB out at any time? might be handy if you stop somewhere and dont want to turn off the car for a quick "run in and out" locking the car is usually recommended

    i had a 2004 that required the Fob to be inserted but that was many many moons ago and never tried it.
     
  6. efusco

    efusco Moderator Emeritus
    Staff Member

    Joined:
    Nov 26, 2003
    19,886
    1,160
    9
    Location:
    Nixa, MO
    Vehicle:
    2004 Prius
    Model:
    N/A
    True Dave, even offers the option of disabling the lock mechanism that holds the key in to allow you to do that.
     
  7. ronhowell

    ronhowell Active Member

    Joined:
    Oct 4, 2007
    681
    32
    0
    Location:
    Cypress, CA.
    Vehicle:
    2008 Prius
    But why the surprise. As qbee42 stated, the car only requires the FOB to be inside the car, where RFID technology senses it; the FOB slot is just a convenient parking space for it while driving. I never use it on my 2008 Prius, I simply keep the FOB in my pocket before pressing the Start button.

    Incidentally, you cannot drive fobless. The FOB has to be present inside the car before it will enter the Ready mode. Not necessarily in the slot though.
     
  8. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
    Staff Member

    Joined:
    May 11, 2004
    14,810
    2,468
    65
    Location:
    Far-North Chicagoland
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    I believe the surprise was in that Tom's explanation came 27 hours after the original post. Learning the answer after asking the question doesn't negate the need to ask the question in the first place.
     
  9. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,037
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    That only works for SKS. The RFID inside the fobs is very short range. It needs to be within inches of the antenna; keeping it in your pocket will not work.

    The non-SKS fobs only have RFID. The SKS fobs have both an active transponder for the smart system, and RFID as a backup.

    Tom
     
    1 person likes this.
  10. RyC

    RyC Junior Member

    Joined:
    Sep 5, 2011
    25
    4
    0
    Location:
    San Luis Obispo
    Vehicle:
    2005 Prius
    Model:
    N/A
    As a side note, on my 2005 Prius with SKS, once I start the car, I can take the smart key fob outside the vehicle, and I can still drive the Prius away. It will still beep and show the dash light, but I can still put it in drive from park, and it seemed to work indefinitely.

    Perhaps the Prius only needs to ensure the key is in the car at startup, and then it doesn't care where the key is?
     
  11. Erik Aalto

    Erik Aalto Junior Member

    Joined:
    Dec 20, 2011
    47
    10
    0
    Location:
    North Carolina
    Vehicle:
    2011 Prius
    Model:
    Two
    My old K5 blazer could be started with the key removed from the ignition, as long as it was not in "locked" position. I used to leave the ignition unlocked most of the time so I only had to use a key for the door.
     
  12. ronhowell

    ronhowell Active Member

    Joined:
    Oct 4, 2007
    681
    32
    0
    Location:
    Cypress, CA.
    Vehicle:
    2008 Prius
    Yes, as I wrote my comment I suspected that a fob without SKS might have different characteristics.

    Thanks for the explanation, Tom.
     
  13. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,037
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    Some Jeeps were like that too. It is very handy when you live in a safe community.

    Tom
     
  14. qbee42

    qbee42 My other car is a boat

    Joined:
    Mar 2, 2006
    18,058
    3,037
    7
    Location:
    Northern Michigan
    Vehicle:
    2006 Prius
    Correct. Requiring the key to drive is considered a safety issue: What happens if the fob battery dies when driving down the road? What happens if RF interference jams the signal?

    Tom
     
  15. TonyPSchaefer

    TonyPSchaefer Your Friendly Moderator
    Staff Member

    Joined:
    May 11, 2004
    14,810
    2,468
    65
    Location:
    Far-North Chicagoland
    Vehicle:
    2017 Prius Prime
    Model:
    Prime Advanced
    If you dig deep enough, you can find posts in which people leave their fobs somewhere and drive off. There was one instance of a man driving to the airport and his wife driving home. Dangest thing, though, when she went to drive the car later the same day, she couldn't find the fob. Turns out it was in his coat pocket. Several states away!
     
  16. kornkob

    kornkob New Member

    Joined:
    Dec 20, 2011
    128
    15
    0
    Location:
    Wisconsin
    Vehicle:
    2009 Prius
    Model:
    ----USA----
    Seems to me that someone with a little electrical knowledge could probably mod that RF reader with a boosted signal so that non SKS could be read further away (IE from inside your pocket)
     
  17. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

    Joined:
    Apr 13, 2004
    15,140
    610
    0
    Location:
    South Puget Sound, WA
    Vehicle:
    2013 Nissan LEAF
    Model:
    Persona
    dont you have to boost the FOB? a receiver is just that... a receiver. it like catching a ball from someone standing 100 feet away who can only throw 50 feet.

    nice idea but the thought of changing the battery every 6 months is not appealing
     
  18. Danny Hamilton

    Danny Hamilton Active Member

    Joined:
    Apr 30, 2007
    926
    92
    0
    Location:
    Greater Chicagoland Area
    Vehicle:
    2007 Prius
    Model:
    N/A
    Not sure how the RFID in the Prius Fob works, but in many RFID applications there is no battery connected to the RFID chip.

    In RFID applications without a battery (such as in the chips imbedded in pets) The reader sends an encoded radio signal to the RFID chip, the changing magnetic field of the radio wave induces an electric current in the chip. This induced current is used to transmit the encoded RFID value back to the reader.

    So, if this is how it works in the Prius FOB, then you would have to modify the reader to send a strong enough signal to induce enough current in the RFID chip at the significantly increased distance from the reader. Then you would need the RFID to transmit back a strong enough signal to the reader. Perhaps adding an induction coil (or improving the one that is there?) to the RFID chip?

    You could reduce the power needed by moving the RFID reader closer to your pocket. Maybe install it in the center console? or in the driver seat?
     
  19. DaveinOlyWA

    DaveinOlyWA 3rd Time was Solariffic!!

    Joined:
    Apr 13, 2004
    15,140
    610
    0
    Location:
    South Puget Sound, WA
    Vehicle:
    2013 Nissan LEAF
    Model:
    Persona
    ah sooo??? ok. sounds like it would be a huge boost in signal to a completely different format i am guessing. isnt RFID used extensively due to its cheap cost? this would definitely realign the price to something probably close to the SKS prices
     
  20. JonGraham

    JonGraham Junior Member

    Joined:
    Oct 24, 2011
    10
    0
    0
    Location:
    Rockford
    Vehicle:
    2006 Prius
    Model:
    N/A
    I have an '06 Prius and I have to put the FOB in the slot to start it, and after it's started the FOB won't come out. What does this mean? "True Dave, even offers the option of disabling the lock mechanism that holds the key in to allow you to do that."
     
Loading...