Repair advice. Bad Cat and Coolant system.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by MonkButter, Aug 29, 2025 at 1:48 AM.

Tags:
  1. MonkButter

    MonkButter Junior Member

    Joined:
    May 19, 2019
    4
    0
    0
    Location:
    Ny
    Vehicle:
    2007 Prius
    Model:
    N/A
    Failed inspection due to emissions (P0420) and cylinder misfires. Changed my spark plugs today and all misfire codes stopped but new codes came on. P1116, P1117 and P1121. Topped my coolant tank which was very low but still popping on with the temperature warning and red triangle.

    Ran dr Prius battery life test with my OBD2 and scored 85% but it does say it’s running warm,

    You guys think with the Cat P0420 and coolant issues it’s worth repairs? 2007 with 250k. Today while flushing Cat cleaner through I lost all acceleration and needed full reset to get home. Not sure what to do.
     

    Attached Files:

    #1 MonkButter, Aug 29, 2025 at 1:48 AM
  2. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    12,551
    2,226
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    Get your coolant filled first. Needs stand at top of filler neck 5 min without dropping leveltop off jug and cap. That'll make all your coolant sensors definitely be submerged . Clear codes . Drive and see .
     
    #2 Tombukt2, Aug 29, 2025 at 2:11 PM
  3. Brian1954

    Brian1954 Senior Member

    Joined:
    Jan 31, 2021
    1,935
    765
    0
    Location:
    South Central PA, USA
    Vehicle:
    2011 Prius
    Model:
    III
    Did you check the coolant level inside the radiator? You need to remove the metal radiator cap to check the level. The plastic tank is just an overflow.

    What app are you using to scan for trouble codes? I am asking because it looks like it is not capable of reading all the trouble codes that the car has. Based on the picture of the warning lights on the dashboard, you have codes for the brake system, TPMS, and hybrid control system, which the app that you are using, are not being reported.

    You need a better scan tool to read all the codes that the car is trying to tell you about. Read post #1 and then scroll down to post #37 in this thread, https://priuschat.com/index.php?posts/3246758
    The Autel AP200 is a very capable scanner for your Prius and costs about $60 on Amazon.
     
    #3 Brian1954, Aug 29, 2025 at 5:57 PM
  4. Tombukt2

    Tombukt2 Senior Member

    Joined:
    Nov 29, 2020
    12,551
    2,226
    0
    Location:
    Durham NC
    Vehicle:
    2009 Prius
    Model:
    Base
    You need to bust open your radiator and top off the coolant until it stands at the top of the filler neck for 5 minutes without dropping then ride and check for the codes again
     
    #4 Tombukt2, Aug 29, 2025 at 7:01 PM
(You must log in or sign up to post here.)