T-SB-0054-24

Discussion in 'Gen 5 Prius Care, Maintenance and Troubleshooting' started by flyboy09, Apr 13, 2025 at 10:33 AM.

  1. flyboy09

    flyboy09 Junior Member

    Joined:
    May 11, 2005
    63
    4
    0
    Location:
    Seymour Tennessee
    Vehicle:
    2005 Prius
    Model:
    N/A
    T-SB-0054-24
    how to you check to see that the ECU has been updated? Toyota dealer claims that the update has been completed, yet this morning after a full traction battery charge the 12 volt battery indicates 12.2 volts and recommends it needs to be recharged.
     
    #1 flyboy09, Apr 13, 2025 at 10:33 AM
  2. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    25,865
    16,886
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Usually a TSB that calls for a firmware update will show the revision number (they usually call it a "calibration ID") that the ECU should be updated to. So you connect with Techstream or another scan tool that shows your ECUs' calibration IDs, and you see if it's now the one specified in the TSB.
     
    #2 ChapmanF, Apr 13, 2025 at 12:31 PM
  3. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    111,416
    50,743
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    without knowing the condition of the battery prior to the tsb being performed, they very well could have.
    it won't fix a damaged battery. if it fails, they will replace under warranty. it wouldn't hurt to give it a full charge and then check it regularly
     
    #3 bisco, Apr 13, 2025 at 1:20 PM
  4. flyboy09

    flyboy09 Junior Member

    Joined:
    May 11, 2005
    63
    4
    0
    Location:
    Seymour Tennessee
    Vehicle:
    2005 Prius
    Model:
    N/A
    this is the second 12 volt battery under warrant. the replacement battery has 470 cca and is 3 months old. interesting observation by me is when the traction battery begins to charge, the 12 volt battery shows 14 volts when checked with a volt meter...the toyota mechanic at the dealer said that the traction battery charge cable does not charge the 12 volt battery. who am i to argue? i must be hallucinating.
     
    #4 flyboy09, Apr 13, 2025 at 8:53 PM
  5. BiomedO1

    BiomedO1 Senior Member

    Joined:
    Mar 27, 2021
    2,512
    1,334
    0
    Location:
    SacTown, Ca
    Vehicle:
    2021 Prius Prime
    Model:
    LE
    The 12V battery is ONLY receiving a charge while the traction battery is charging. If the traction battery isn't charging the 12V battery isn't charging; just because it's plugged in. At least that's how it works on the gen4. That's why the OM states to disconnect the charging cable when traction battery charging is complete. While charging cable is connected to the car, the car is doing more frequent diagnostic checks using the 12V battery ONLY and drawing it down...

    FWIW: I'm still on my original OEM battery...
     
    #5 BiomedO1, Apr 13, 2025 at 10:29 PM
    Last edited: Apr 13, 2025 at 10:34 PM
(You must log in or sign up to post here.)