P1121 Fail fix

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by PrestonH2O, Aug 10, 2025.

  1. PrestonH2O

    PrestonH2O New Member

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    II
    I tried to fix my p1121 error code by replacing the 3-way coolant control valve. I even got OEM.

    I ended up spilling all the coolant on the ground. I also had to take one of the hoses off the coolant pump which I then forgot to put back on when I started the car. I then put it back on once I realized my mistake. I have refilled, and possibly overfilled the coolant system but the coolant doesn't seem to be circulating. The coolant system also seems to be making a weird noise like it is trying to pump and getting nothing? Could there be air in the system?

    I am having the following error codes now:

    P0117
    P1121 - still, even after clearing code
    P0A0D - I triple checked the service plug and I am pretty sure its all the way in and pushed down! The red triangle goes on and off.

    Any idea what the problem could be? Did I break the pump or put air in the system?
     
  2. PrestonH2O

    PrestonH2O New Member

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    Update: I am now ONLY getting P0A93. Also at one point all the lights on the dash went on including the E-break light and it started beeping really loud but that stopped and hasn't happened again.
     
  3. Tombukt2

    Tombukt2 Senior Member

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    Take rad cap off . If coolant is not sitting at top of neck you is not full now pour a stream of red in neck . Sloooowly. When you finally get it to stand at the top of the neck for 5 minutes you're full that's going to take you 40 minutes and a quart or better of coolant let me know you gonna be pouring 20 35 min . It goes slow . Obviously make sure all hoses are on and clamped not hanging
     
  4. dolj

    dolj Senior Member

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    By chance, did you unplug the inverter coolant pump and overlook reconnecting it?

    Prius Gen II Inverter 1 Pump.jpg
     
    saneesh8 likes this.
  5. PrestonH2O

    PrestonH2O New Member

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    Hey turns out I am a moron, I didn't realize there are two separate coolant revivors. I went ahead and refilled the one that actually got emptied and the car now has no issues. Yay :D
     
    frodoz737 and Brian1954 like this.
  6. pasadena_commut

    pasadena_commut Senior Member

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    Not quite. There is probably still air in the ICE coolant loop. Minimally the OP should each morning check the coolant levels in the overflow tank and at the radiator neck until the coolant levels stop changing.