1. Attachments are working again! Check out this thread for more details and to report any other bugs.

Smart Key won't work even with new battery

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by turbo5spd-prius, Jun 29, 2024.

  1. turbo5spd-prius

    turbo5spd-prius Junior Member

    Joined:
    Aug 27, 2023
    55
    14
    0
    Location:
    United States
    Vehicle:
    2005 Prius
    Model:
    Two
    My car wouldn't start unless I put the fob in the dash insert. I replaced the battery but it still won't work without being in the dash.

    The old cell, less than a year old is 3.1V. The new is 3.3V

    What might I be missing?
     
  2. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,003
    49,983
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    does the fob light come on when you press a button?

    how is the 12v health?
     
  3. turbo5spd-prius

    turbo5spd-prius Junior Member

    Joined:
    Aug 27, 2023
    55
    14
    0
    Location:
    United States
    Vehicle:
    2005 Prius
    Model:
    Two
    The 12V battery seems fine at 12.6V measured under hood.
     
    #3 turbo5spd-prius, Jun 29, 2024
    Last edited: Jun 29, 2024
  4. turbo5spd-prius

    turbo5spd-prius Junior Member

    Joined:
    Aug 27, 2023
    55
    14
    0
    Location:
    United States
    Vehicle:
    2005 Prius
    Model:
    Two
    The light does flash on the fob. I measured 12.6V under the hood between the jumper terminal and chassis.

    I guess I'll add that the remote locks work fine, just no proximity functions (button on door, starting without it in the dash).
     
    #4 turbo5spd-prius, Jun 29, 2024
    Last edited: Jun 29, 2024
    bisco likes this.
  5. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,232
    1,770
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Have you replaced the case that's on the fob did you forget the transponder chip?
     
  6. turbo5spd-prius

    turbo5spd-prius Junior Member

    Joined:
    Aug 27, 2023
    55
    14
    0
    Location:
    United States
    Vehicle:
    2005 Prius
    Model:
    Two
    No, I hadn't. I just found the problem. Apparently I accidentally hit the "key" button under the dash recently fumbling for the hood latch at night.

    Solved.

    Thanks everybody for your input.
     
    Brian1954 and bisco like this.
  7. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    10,232
    1,770
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Yep that's pretty common.
     
  8. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,003
    49,983
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    I always forget that