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P1121 can it mean something else??????

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by terramir, Apr 1, 2019.

  1. terramir

    terramir Member

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    Hi help,
    replaced my coolant valve with a dorman, they are usually pretty good when it comes to aftermarket parts, and seems like everything is working i.e. heater and well the engine does get a heat boost from the thermos as far as I can see with hybrid assistant.
    But the p1121 keeps coming back. question is could this be due to an incomplete bleed or can this code mean something else?

    terramir
     
    #1 terramir, Apr 1, 2019
  2. ChapmanF

    ChapmanF Senior Member

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    There was a very recent thread, like just the last few days, also about a P1121, and I summarized what the detection conditions are for that code, and somebody else posted the workup section from the manual. You can probably search it up without much trouble.

    What a code means is/are its detection conditions. It isn't telling you what is wrong with the car, or what part to replace; it is telling you the computer sensed the conditions that are programmed to trigger that code. In this case, the conditions have to do with the coolant temperature sensed at the thermos outlet, and the position feedback voltage returning from the valve.

    The computer can't give you a code that tells you why those conditions exist, or what to do about them. it can only tell you what conditions were sensed. The interpretation is the job for the human. The workup section in the manual will help.
     
    #2 ChapmanF, Apr 1, 2019
    SFO likes this.
  3. M in KC

    M in KC Active Member

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    terramir, was the initial and subsequent code retrieved with a Pri compliant reader? Generic OBDII readers can not and should not be relied upon for code retrieval for these cars.

    Second Dorman, IMO does not generally make pretty good aftermarket parts. These are fairly sophisticated cars, generally its worth your time and your money to purchase Toyota replacement parts for repairs.
     
    #3 M in KC, Apr 2, 2019
  4. terramir

    terramir Member

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    the one thing that is disturbing about this is that the old valve made noises all the time, I posted the noises here and they told me that is the 3way coolant valve not being able to get into position and that it keeps retrying. this noise is gone now.
    one of the things I just saw in the list that is in the other post is coolant obstruction I figure I should probably drain the coolant buy 4-6 gallons of distilled water run that and dump that a few times and see how much crap comes out of the cooling system. this is a 15 year old car and one thing I can say a bunch of crap came out of the inverter loop when I flushed that about a year ago, so yeah gotta order some more coolant and then stop by a store to buy distilled water. but thousand oaks Toyota won't have my orders ready for like two, three days I guess I'll be doing this this weekend. should have just flushed it when I was installing the part instead of trying to cheap out. we'll see if this solves anything.
    terramir
     
    #4 terramir, Apr 2, 2019
  5. ChapmanF

    ChapmanF Senior Member

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    Do you have Techstream? Do you have some way to watch the coolant temperature and valve position readings? Have you looked at the troubleshooting section from the manual?
     
    #5 ChapmanF, Apr 2, 2019
  6. terramir

    terramir Member

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    yeah If I can find my old laptop in my mess I can do. .right now best I can do is use my obdIIlx and hybrid assistant to monitor the engine water temp, but yeah I need to dig out that cable and stuff
    terramir
     
    #6 terramir, Apr 2, 2019
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