2009 Prius P1121

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by PriusGenxFixer, Feb 27, 2026 at 3:37 PM.

  1. PriusGenxFixer

    PriusGenxFixer New Member

    Joined:
    Tuesday
    6
    1
    0
    Location:
    Colorado
    Vehicle:
    2007 Prius
    Model:
    II
    Team
    I have a 2009 Prius that has P1121 come up periodically
    Bought it used. Ran well for 5 years.
    Triangle of death with P1121 (after 5 years)
    Check engine again after 2 years
    Secong Check engine again after 2 more years
    I used an Coolant Control Value the first two times from Amazon. Check engine would go away after about 30 min of running vehcile

    What are your thoughts on the amazon product not being of good quality and if i need to go to a OEM Toyota unit
     
    #1 PriusGenxFixer, Feb 27, 2026 at 3:37 PM
  2. saneesh8

    saneesh8 Member

    Joined:
    Jul 5, 2024
    209
    52
    0
    Location:
    Allen, TX
    Vehicle:
    2009 Prius
    Model:
    One
    Aftermarket, avoid.. So many fake items. Just get the OEM.

    How many miles on it? i have the same year.. almost 158k on it.
     
    #2 saneesh8, Feb 27, 2026 at 4:57 PM
  3. PriusGenxFixer

    PriusGenxFixer New Member

    Joined:
    Tuesday
    6
    1
    0
    Location:
    Colorado
    Vehicle:
    2007 Prius
    Model:
    II
    I have 160k too :)
    I ordered one from ourismantoyotaofrichmond website. Had good reviews
     
    #3 PriusGenxFixer, Feb 27, 2026 at 5:35 PM
    Brian1954 likes this.
  4. BiomedO1

    BiomedO1 Senior Member

    Joined:
    Mar 27, 2021
    4,018
    2,109
    0
    Location:
    SacTown, Ca
    Vehicle:
    2021 Prius Prime
    Model:
    LE
    Have you tried flushing out your cooling system? You may have junk mechanically jamming up that switch valve or it could just be the cheap counterfeit part. :mad:o_O:whistle:
     
    #4 BiomedO1, Feb 27, 2026 at 6:20 PM
(You must log in or sign up to post here.)