ECM & Coolant Pump Error Codes - U0293, P261C

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by Prius C Lover, Oct 30, 2025 at 7:11 AM.

Tags:
  1. Prius C Lover

    Prius C Lover New Member

    Joined:
    Thursday
    4
    1
    0
    Location:
    Nashville,TN
    Vehicle:
    2012 Prius c
    Model:
    Two
    I have the following error codes: U0293, P261C

    I inspected the water pump and replaced it with a new OEM one but the error codes did not clear.
    All fuses are good but I am not positive about the more advanced relays and wiring.

    She’s got 200,000 + miles and I’d like to keep her going strong.

    Any help is appreciated.
    TIA,
     
    #1 Prius C Lover, Oct 30, 2025 at 7:11 AM
  2. Brian1954

    Brian1954 Senior Member

    Joined:
    Jan 31, 2021
    2,088
    812
    0
    Location:
    South Central PA, USA
    Vehicle:
    2011 Prius
    Model:
    III
    Which water pump did you replace? The engine water pump or inverter water pump?
     
    #2 Brian1954, Oct 30, 2025 at 5:40 PM
  3. Prius C Lover

    Prius C Lover New Member

    Joined:
    Thursday
    4
    1
    0
    Location:
    Nashville,TN
    Vehicle:
    2012 Prius c
    Model:
    Two
    Engine Water pump.
     
    #3 Prius C Lover, Oct 30, 2025 at 6:35 PM
    Brian1954 likes this.
  4. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

    Joined:
    May 12, 2018
    8,048
    7,528
    1
    Location:
    Pennsylvania
    Vehicle:
    2018 Prius c
    Model:
    Two
    Your post doesn't quite make it clear- did you clear the codes using your diagnostic tool?

    Just replacing a broken part does not clear the related code(s). You have to do that yourself.
     
    #4 Leadfoot J. McCoalroller, Oct 30, 2025 at 7:42 PM
  5. Prius C Lover

    Prius C Lover New Member

    Joined:
    Thursday
    4
    1
    0
    Location:
    Nashville,TN
    Vehicle:
    2012 Prius c
    Model:
    Two
    yes, I’ve cleared the codes but they came back on.
     
    #5 Prius C Lover, Oct 30, 2025 at 8:46 PM
  6. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

    Joined:
    May 12, 2018
    8,048
    7,528
    1
    Location:
    Pennsylvania
    Vehicle:
    2018 Prius c
    Model:
    Two
    Then this is more likely a wiring issue.

    I would consult the official repair manual. It contains specific step-by-step procedures to test the wiring, it's a great resource.

    You can get an inexpensive short term subscription from Toyota, information on this link.

    Good luck!
     
    #6 Leadfoot J. McCoalroller, Oct 31, 2025 at 7:23 AM
    Prius C Lover and Brian1954 like this.
  7. Prius C Lover

    Prius C Lover New Member

    Joined:
    Thursday
    4
    1
    0
    Location:
    Nashville,TN
    Vehicle:
    2012 Prius c
    Model:
    Two
    I’m at the step for testing the power at the water pump connector while the ignition is turned to the ON position. I’m not getting power when I test for DC voltage with a multimeter or with a 12V Circuit Tester.

    It could be the wiring harness or the ECM.
     
    #7 Prius C Lover, Nov 1, 2025 at 1:23 PM
  8. Leadfoot J. McCoalroller

    Leadfoot J. McCoalroller Senior Member

    Joined:
    May 12, 2018
    8,048
    7,528
    1
    Location:
    Pennsylvania
    Vehicle:
    2018 Prius c
    Model:
    Two
    I don't have an active subscription right now so I can't do anything to verify your progress. That said, if the manual has you down to wires vs. ECM it's almost always the wires.

    You can use the included electronic wiring diagram to work out where the other end of that wire is and do a basic continuity check from pin to pin.
     
    #8 Leadfoot J. McCoalroller, Nov 1, 2025 at 2:34 PM
    Prius C Lover likes this.
  9. ChapmanF

    ChapmanF Senior Member

    Joined:
    Mar 30, 2008
    27,343
    17,943
    0
    Location:
    Indiana, USA
    Vehicle:
    2010 Prius
    Model:
    IV
    Is that on +B, or on NWP (WPI)?
     
    #9 ChapmanF, Nov 1, 2025 at 3:46 PM
(You must log in or sign up to post here.)