Keyless Entry not responding 2013 Prius C 1

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by Royce Rezendes, Sep 27, 2022.

  1. Royce Rezendes

    Royce Rezendes Junior Member

    Joined:
    Jun 21, 2013
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    Location:
    Lawrence, KS
    Vehicle:
    2013 Prius c
    Model:
    One
    First off my car is a 2013 Prius C 1 that I bought brand new. I have zero other issues with the car and there are no warning lights or codes that come up through the OBD2 port.

    Keyless entry (non smart key) just the Lock/Unlock/Alarm buttons on my keyfob stopped working. I replaced the battery and made sure it had good voltage and still nothing. I purchased a rtl-sdr radio receiver and was able to monitor the 315 Mhz range and saw that every time I press a button, a signal was being transmitted from the fob. The mechanical key and lock/unlock buttons inside the car still function perfectly. My auxiliary 12V battery shows 12.28 V on my multimeter while car is off, although it is the original oem battery from 2013 (again no other issues in the car). I tested with a multimeter all Relays and Fuses, every single one is fine. I removed the door/tpms receiver module to inspect the electronics and everything looks pristine on it, I noticed there was no power whatsoever showing up on the connector that supplies it power inside the car. I assume there should be 12V there even when the car is off because you can always use your key fob to lock/unlock when car is off. This happened out of nowhere, nothing happened, didn't drop the keyfob or have anything happen on the day it stopped working. All I can think is the wiring is disconnected or broken somewhere inside the car from the battery to the connector that supplies the receiver module. One thing to note is that a few weeks prior to the key fob stopping working I actually ran into a parking pole on the driver's side front wheel well, maybe some wire on that fender got pinched? I don't know what to do/test next, I want to avoid paying hundreds of dollars to a dealership if at all possible.
     
    #1 Royce Rezendes, Sep 27, 2022
    Last edited: Sep 27, 2022
  2. Royce Rezendes

    Royce Rezendes Junior Member

    Joined:
    Jun 21, 2013
    11
    3
    0
    Location:
    Lawrence, KS
    Vehicle:
    2013 Prius c
    Model:
    One
    So, I feel stupid and the issue is basically fixed (pending me buying a good battery). I supplied the keyfob with 3.1V directly from my bench power supply and it works. Even though the fresh out of the pack (Amazon likely) battery reads 3.27V. So I guess the battery couldn't provide enough Amps? I'll be heading to Walgreens...
     
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  3. bisco

    bisco cookie crumbler

    Joined:
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    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    please let us know the outcome. is the battery connector tight? did you have pos and neg correct?
    a new fob battery should measure 3.3v
     
  4. Royce Rezendes

    Royce Rezendes Junior Member

    Joined:
    Jun 21, 2013
    11
    3
    0
    Location:
    Lawrence, KS
    Vehicle:
    2013 Prius c
    Model:
    One
    Yes, bought a new battery (measuring 3.3v) and it works perfectly. So even though when you look up a cr2016 battery it says it's only 3v, I guess it must be 3.3v and anything lower means the battery is dying/dead, even 3.27v. Or the batteries I have are fake/low quality.
     
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  5. bisco

    bisco cookie crumbler

    Joined:
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    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    a lot of low quality stuff online unfortunately. it's hit or miss.

    all batteries have a 'nominal voltage rating' but are higher than that when new and fully charged
     
    Royce Rezendes likes this.
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