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Smart Key Weirdness

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by efusco, Jul 1, 2009.

  1. efusco

    efusco Moderator Emeritus
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    My smart key fob works perfectly.
    My wife's smart key fob has behaved oddly. We blamed it on the battery being bad initially since the sks for both the doors and the starter would not work. But she almost never drives my car so it hasn't been a big deal and I assumed the replacement of the battery would solve the issue.

    But, tonight we went out to a movie. All was fine until we got there and I tried to lock the car (using the sks black button on the door handle). It wouldn't lock, no beep, nothing. Hmmm, I check my pockets to find that I do NOT have my key fob. I have my wife check and sure enough she has hers. Still can't lock the car with SKS, but it will work by pushing the "lock" button on the fob.

    Likewise, after the movie, the car would not unlock with the sks, but only by hitting the button on the fob. But once in the car it started via sks just fine.

    Again, my fob works fine inside and out, but my wife's fob works only inside.

    Never heard this issue before. Anyone got any ideas here? Patrick? Nikki? Prius Team??
     
    #1 efusco, Jul 1, 2009
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Evan,

    I'm assuming that your query is regarding your 2004 (just checking, since this was posted in a 3G forum.)

    Knowing that your wife had the fob and you did not, did she depress the black square button on her side of the vehicle when you needed to lock it? The Smart function will not work unless the fob is within 3 ft of the button being pressed.

    If you lock the Prius using the fob lock button, then the Smart system will be temporarily deactivated and you must use the fob unlock button when it is time to reenter the car. This works well if you want to store a Smart fob within the locked Prius.

    Did your wife's fob always lack full Smart functionality; or did it only recently start to lose this functionality?
     
    #2 Patrick Wong, Jul 2, 2009
  3. HTMLSpinnr

    HTMLSpinnr Super Moderator
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    (relocated to the Gen II forum)

    I actually had this issue in the 2004 and ended up replacing the batteries in the FOB. As the car has aged it seems that it's been becoming less sensitive. That, and the cheap Wal-Mart CR2032 batteries just aren't as long lasting. I also found that a "good" 12V AUX battery makes a bit of a difference.
     
    #3 HTMLSpinnr, Jul 2, 2009
  4. RobH

    RobH Senior Member

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    I'd recommend checking the range of the two keyfobs. The first test is how far away you can be for the buttons to work. The second test is the SKS detection range. The red LED on the upper right corner of the keyfob will blink when the proximity detection first occurs. You can also hear the proximity detection by tuning an AM radio to 269 KHz, where the 2nd harmonic of the 134.5 KHz signal of the door transmitters occurs. The radio has to have support for the long wave band, so it's a rather specialized unit, typically advertised as a short wave receiver (but including the long wave band).

    Did you actually change the battery in the bad keyfob? My guess is that the range of the bad unit is shorter, either due to the battery or perhaps corrosion. If the button press range is normal, then it would seem that the receiver in the keyfob has gone bad.
     
    #4 RobH, Jul 2, 2009
  5. HTMLSpinnr

    HTMLSpinnr Super Moderator
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    Right - despite the lithium type battery, it doesn't hurt to clean the battery contacts with a swab and isopropyl alcohol (91% or anhydrous if possible) or electronics cleaner.
     
    #5 HTMLSpinnr, Jul 2, 2009
  6. efusco

    efusco Moderator Emeritus
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    I'll double check those ideas guys. But yes, I did change the battery myself. The fob worked perfectly for about 3-4 years and only in the past year or so started acting funny. But, as I said, I figured it was the battery and replaced it and figured it was fine.

    Patrick, the first two attempts to lock I did not have the fob so it wasn't w/in 3 ft. of the lock. The third attempt it was. I think tried to unlock with the fob in my pocket and it didn't work (after the movie).

    I'll go fiddle with it a bit in a minute.
     
    #6 efusco, Jul 2, 2009
  7. galaxee

    galaxee mostly benevolent

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    E, put the fob in the dash slot. that should re-sync it.
     
    #7 galaxee, Jul 11, 2009
  8. efusco

    efusco Moderator Emeritus
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    Thanks Nikki,
    I actually went out and tested the fob and it seemed to work perfectly on all doors and to start the car. But if it should start acting goofy again I'll remember that trick.
     
    #8 efusco, Jul 11, 2009
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