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2005 Prius Ate Key Fob, Not Starting or Turning Off -- Not Batteries... ?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by smittens, Jan 11, 2023.

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  1. smittens

    smittens New Member

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    I don't think this is either of the usual dead battery issues, as those are both only a few years old.

    I sat in my car, on with the fob inserted, in the rain today for about 30 minutes when it flashed an error about "Unable to Engage Park Mode, or similar". I turned it off, and 30 minutes later tried to turn it back on, but it wouldn't start. All warning indicators turn on (see Photo 1) and the car makes a small noise but not normal ignition sounds

    Then, worse, I cannot turn it off all the way! Sometimes all dash lights go off, but the Key Fob does not release, and the the small green light on the manual parking break button flashes without stopping.

    Trying other methods, such as holding the Power button, with & without break, for long or short periods of time did not much help. Fob still stuck, cannot fully turn care on or off.

    Sometimes the Shift position indicators would flash squares, around each [R] [P] [N] [D] letter (see Photo 2, edited to show squares more clearly) as it failed to turn on/off, and then those wouldn't go off at all until I kept pushing things!

    Tried different things for ~5 minutes, waited 15 mins and researched suggestions online, then tried again and finally something got it to shut all the way off and release my Key Fob. Now planning on towing to the mechanic tomorrow unless I can figure out anything better to do.

    Any idea what could be going wrong?

    Photo 1:
    [​IMG]

    Photo 2:
    [​IMG]
     
    #1 smittens, Jan 11, 2023
  2. bisco

    bisco cookie crumbler

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    were you sitting for the 30 minutes with the car ready and the engine turning on and off?

    if it was not ready, you killed the 12v.

    if it was, maybe you ran out of gas?
     
    #2 bisco, Jan 11, 2023
  3. TMR-JWAP

    TMR-JWAP Senior Member

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    The gear position indicators flashing is sometimes indicative of a 12v battery that's only around 9 volts........
    perhaps you drained the 12v battery sitting in the rain listening to the radio with the fan running or something similar, while the car was not in ready?
     
    #3 TMR-JWAP, Jan 11, 2023
  4. JeffAnd

    JeffAnd Junior Member

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    How bright is the dome light. A dim battery would be an indication of a low 12 volt battery voltage. When you start the prius you step on the brake pedal. This will cause the brake lights to come on. This additional load can cause the battery voltage drop. If this is happening you will see the dome light reduce it brightness.
     
    #4 JeffAnd, Jan 12, 2023
  5. smittens

    smittens New Member

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    Thanks for the suggestions! It looks like the issue was my Key Fob battery dying while it was in the ignition!

    The battery had been too low for remote functions for over a month, but I thought there was no issues with just inserting it for driving & using the manual key for opening/locking

    Wellll it turns out that if the fob really REALLY drains, even while in the ignition, the car will start freaking out & doesn't want to release it!

    But I popped in a new mini battery and everything is right as rain!
     
    #5 smittens, Jan 12, 2023
    bisco likes this.
  6. dolj

    dolj Senior Member

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    If the 'load' of a handful of LED lights coming on was enough to tip a 12 V battery over the edge (dim the dome light), I'd say skip any further testing and go straight to replacing the battery.
     
    #6 dolj, Jan 12, 2023
  7. JeffAnd

    JeffAnd Junior Member

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    Make sure the wipers and head light switch is in the off position. This will also help reduce load on the 12 volt battery.
    When the key fob is placed in the slot in the dash it switches on a coil. The coil produces a alternating magnetic field around key fob. This powers up the little black transponder chip that's not mounted on the circuit board. The car can now read the transponder chip ID number. All the while the key fob is left in the dash it's using power.
     
    #7 JeffAnd, Jan 18, 2023
    Last edited: Jan 18, 2023
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