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remote key won't unlock door

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by tombone, Jan 17, 2011.

  1. tombone

    tombone New Member

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    Hi-I'm a newbie here. I traded my 2005 prius a year and a half ago for an '08 which apparently was a rental car for 40K miles before me. It came with only one key(not a SKS)which recently quit unlocking the doors and hatch remotely. I looked under the steering column and there is only a reset button for the tire sensor guage, and a couple blanks, presumably one would be for the remote/smart key reset.
    I am currently using the enclosed key to manually unlock the doors. The remote works as usual when I place it in the slot to start the car. I live an hour plus from the closest dealers, and would love to address this issue without having to go there. I checked the FOB battery and even replaced it, although the voltage was practically identical between the existing battery and a new one. The little red light is operational when i press lock/unlock. The car stays outside - i don't have a garage, and remains unlocked between trips. Recently it sat for several days in the last large snowstorm. When I finally drove it up the 1/3 mile driveway, it would not lock when i was ready to leave it up on the 'hard road'. I've checked out a few related threads, but haven't hit on this issue yet. Perhaps the 12V battery is weak?
     
  2. qbee42

    qbee42 My other car is a boat

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    The RFID portion of the fob used to start the car is unrelated to the radio part used to unlock the car. This is why your fob still works to start your Prius even if the fob battery is dead.

    The most common cause of your trouble is a dead fob battery. If you are *certain* that the fob battery is good, then you may have a dead fob. Without a working fob, you can't go through the programming cycle to see if that's the problem. This means you will need the help of a dealer if it is something other than a dead fob battery.

    Tom
     
  3. richard schumacher

    richard schumacher shortbus driver

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  4. tombone

    tombone New Member

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    thanks, guys. the voltmeter said 12.2-12.3; that is a couple tenths lower than my other vehicles showed. my finacees prius showed about 12.4 i'm going to walk back up and try to perform the on dash volt test. this is complicated in that the car is about 1/4 mile from the house up a snowy driveway. whee!
     
  5. tombone

    tombone New Member

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    follow up: i got myself to a dealer, after getting the on dash 12V results, which were a little low, but acceptable (it is winter, and this is an outdoor car). i was ready for a new battery, but ended up paying for the diagnostic, which showed that the memory was gone on the computer which reads the signal from the fob. their brief explanation and warning: in most cases the key is pressed and repressed too quickly, therefore overloading the computer with commands. at some point it balks. recommendation: wait a second or so after pressing the key for the system to digest the command and act before pressing again...not sure if that is what did me in, but this is the knowledge i paid for in time and diagnostic cost....
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    I recommend that you invest in a second fob now. The cost of programming a new fob will be much higher if you lose the remaining fob.

    Fascinating.