Keys and door lock/unlock are now useless

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by mcslain, Jun 22, 2010.

  1. mcslain

    mcslain Junior Member

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    All of a sudden both of the keys that I have for my Prius stopped automatically unlocking my car doors when I get near my car. Even pressing lock/unlock doesn't work. The buttons on the doors themselves don't even work. I thought pressing the 'key' button under the steering wheel would fix this, but it seems to have no effect. Does anyone have any idea what might be wrong? This is getting a bit annoying... It's like having a regular car.

    Thanks
    mcslain
     
    #1 mcslain, Jun 22, 2010
  2. Cboehnke

    Cboehnke New Member

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    Have you checked the batteries in the remotes
     
    #2 Cboehnke, Jun 22, 2010
  3. firepa63

    firepa63 Former Prius Owner

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    The fobs never "automatically" unlock the doors when you get near the car. You have to grab the door handle to activate the unlock function. Check the button under the steering column to make sure you did not accidently turn off your SKS. The button should be in the 'out' position for the SKS to work.
     
    #3 firepa63, Jun 23, 2010
  4. Mike Dimmick

    Mike Dimmick Active Member

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    Could be that the Certification ECU has stopped talking to the Body ECU. The system diagram suggests that on a car with Smart Key, the Certification ECU is responsible for handling button pushes on the keyfob as well as the 'smart' functions. (On a car without Smart Key this function is performed directly by the Body ECU.)

    Having said that, the BEAN bus (on which the two ECUs communicate) is connected as a loop starting and finishing at the Gateway ECU (which reflects messages to and from AVC-LAN for the display, and CAN for the more complex ECUs like Hybrid Vehicle ECU and Engine ECU), going via the Power Source Control ECU (monitors power button), Combination Meter (dashboard lights), Tire Pressure Warning (if fitted), Certification ECU, Transmission Control ECU (moves the parking pawl in the transmission), ID Code Box (verifies the ID of a keyfob slotted into the dash), Body ECU (door locks, power windows, lighting), and the A/C control assembly. If there was a break or problem with this bus I'd expect some of those other functions to stop working.

    There are some dedicated wires going from the Certification ECU to the Body ECU as well, so it could be a break or short in one of those.

    It's worth checking that your car's 12V auxiliary battery is in good condition first, low voltage here causes innumerable problems. It's possible that the batteries in the fobs would go at about the same time if they're the same age.

    Have you recently had the car serviced? Any chance the dealer accidentally reset all the keys? It is possible to do this with the diagnostic tester/laptop.
     
    #4 Mike Dimmick, Jun 23, 2010
  5. alanh

    alanh Active Member

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    One other thing to check is that lock/unlock button on the inside of the driver's door works. If it doesn't, you may have blown a fuse.
     
    #5 alanh, Jun 26, 2010
  6. mcslain

    mcslain Junior Member

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    Turned out it was the batteries! I just couldn't believe that both of my key fobs would die at the same exact time. I also didn't think it would affect the manually pressed door locks, but I guess it does. So thanks for all the assistance.

    mcslain
     
    #6 mcslain, Jul 8, 2010
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