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

Prime 12v swap. Still getting the Christmas tree

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by FlyMode, May 16, 2024.

  1. FlyMode

    FlyMode Junior Member

    Joined:
    Apr 22, 2023
    11
    12
    0
    Location:
    GTA
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    So my 2018 prime had the much dreaded Christmas tree caused by the dying 12 volt battery. I swapped it out just over a month ago and all was well until today, I was driving back home about 120 km into the journey and the Christmas tree came back. once I got home I checked the voltage and the resting voltage was 12.6, which I believe is good and healthy. Does anyone have any idea what the underlying issue could be or have any tips?!

    Thanks
     
  2. FuelMiser

    FuelMiser Senior Member

    Joined:
    Jun 29, 2008
    1,310
    893
    0
    Location:
    Monument, CO
    Vehicle:
    2016 Prius
    Model:
    Touring
    Do these one at a time. If symptoms better, stop.
    1. Check the tightness of the battery connections. 2. Have the new battery load tested. 3. Remove the negative terminal for 30 seconds and reconnect.
     
  3. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,660
    39,219
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    “Christmas tree” being lights on the dashboard? Get the codes read?
     
    Danno5060 and Brian1954 like this.
  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

    Joined:
    May 12, 2018
    7,427
    6,911
    1
    Location:
    Pennsylvania
    Vehicle:
    2018 Prius c
    Model:
    Two
    There's a really long list of things that can cause your dash to light up like a Christmas tree.

    I agree with FuelMiser, worth checking the tightness of the connections- but loose battery terminals don't usually trigger error codes so there's not a lot of percentage in it.

    Time to get the diagnostic codes read and find out what is really going on.
     
  5. FlyMode

    FlyMode Junior Member

    Joined:
    Apr 22, 2023
    11
    12
    0
    Location:
    GTA
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    I will start here. I drove to work and no issues popped up at all so that's a good start . Easy enough to check these through.

    Yeah I have to purchase my own reader. Every dealership I call in the area is saying 2-3 weeks for even a basic appointment like that. Which is a shame I bought a Toyota for reliability and service. I understand everyone's busy but a quick code read can't even be done for 2 weeks seems a bit odd.

    As soon as I mention warranty to the dealership they instantly change their tone. I've called the four closest to me.
     
    Mendel Leisk likes this.
  6. Mendel Leisk

    Mendel Leisk EGR Fanatic

    Joined:
    Oct 17, 2010
    56,660
    39,219
    80
    Location:
    Greater Vancouver, British Columbia, Canada
    Vehicle:
    2010 Prius
    Model:
    Touring
    GTA is Greater Toronto Area, Ontario, Canada, I'm guessing? A clear/complete explanation of your location will help responders.
     
  7. FlyMode

    FlyMode Junior Member

    Joined:
    Apr 22, 2023
    11
    12
    0
    Location:
    GTA
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    Hey Mendel,

    Yes I'm north of Toronto about 45 minutes located in King Township. Ive reached out to dealerships all the way from ajax, to maple, Whitby, Brampton, Mississauga, Barrie.

    Even if it's an emergency or catastrophic failure I'd have to schedule an appointment with them and the car would sit for roughly 2-3 weeks depending on the location.
     
  8. bisco

    bisco cookie crumbler

    Joined:
    May 11, 2005
    110,118
    50,039
    0
    Location:
    boston
    Vehicle:
    2012 Prius Plug-in
    Model:
    Plug-in Base
    that's the way it is pretty much everywhere these days. some auto parts stores offer free code reading, but they don't always pick up the codes, depending on what ecu is reporting.
    there's a thread here on autel scanners which can read everything
     
  9. Brian1954

    Brian1954 Senior Member

    Joined:
    Jan 31, 2021
    1,097
    408
    0
    Location:
    South Central PA, USA
    Vehicle:
    2011 Prius
    Model:
    III
  10. FlyMode

    FlyMode Junior Member

    Joined:
    Apr 22, 2023
    11
    12
    0
    Location:
    GTA
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    I have a Bluetooth reader, when I originally had the issue it was an absolute list of codes so I came here and between this forum and a buddy I figured it was the 12v. Once I swapped the issue went away. It hasn't been back today so maybe a fluke? If not I'll reread the codes and see what more I need to do
     
  11. Brian1954

    Brian1954 Senior Member

    Joined:
    Jan 31, 2021
    1,097
    408
    0
    Location:
    South Central PA, USA
    Vehicle:
    2011 Prius
    Model:
    III
    What Bluetooth OBD2 adapter and app do you have. Most are not capable of reading all the trouble codes in your Prius. Read post #1 in the thread that I linked to in my previous post.

    If warning lights are on, there are trouble codes that need to be read. I predict the warning lights will return, then come back and post what trouble codes you found.
     
  12. FlyMode

    FlyMode Junior Member

    Joined:
    Apr 22, 2023
    11
    12
    0
    Location:
    GTA
    Vehicle:
    2018 Prius Prime
    Model:
    Prime Premium
    It's a bluetooth OBD2 link unit and the app I believe is called Car OBD plus. I'll have to take a look but once they come back I'll post the screenshot of all the codes