2005 Prius Brake Regeneration Capacitor Failure

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Jerome8898, Jan 7, 2020.

  1. Jerome8898

    Jerome8898 New Member

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    Hi all,
    My sister has a 2005 Prius. The other day, a yellow brake light came on. She had the codes read and got the following:

    -Brake Regeneration Capacitor Failure
    -Capacitor Communication Failure

    Does anyone have any experience with this? Is it something where a new capacitor module can be put in relatively easily?

    Thanks for any help you can give.
    -Jerome
     
    #1 Jerome8898, Jan 7, 2020
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    Please post the actual DTCs (codes) that were offered or read.

    Who did the ODB2 code reading, and do you know which scanning device was used?
     
    #2 SFO, Jan 7, 2020
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  3. TMR-JWAP

    TMR-JWAP Senior Member

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    The only ones close to that wording are

    C1377 Capacitor Malfunction and C1378 (Capacitor Communication Malfunction)

    Any chance she had the 12v battery replaced recently and someone unplugged the capacitor bank to allow better access to the battery? Pinched a wire or forgot to plug it back in all the way?

    This is assuming the brake control power supply capacitor bank is what you are talking about. It's the black box mounted slightly to the driverside of the 12v battery. The 12v battery is mounted in the trunk, at the passenger side rear corner.
     
    #3 TMR-JWAP, Jan 7, 2020
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  4. dolj

    dolj Senior Member

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    Also, check that the brake control power supply is properly bolted down otherwise, it will not be grounded.
     
    #4 dolj, Jan 7, 2020
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