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Pump valve replaced, MPGs up!

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by thisboy47, Jan 25, 2014.

  1. thisboy47

    thisboy47 Junior Member

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    II
    My check engine light was throwing the code P1121 for the coolant flow valve. Toyota replaced it under a warranty enhancement (I have 134k on it), and since then my mpgs have gone from 46 to 50.

    My AC is working much better now, too. My theory is that the valve can be in a semi-failure mode for a long time before throwing a code. Now that My coolant is flowing the way that it should, heat is being disappated more efficiently.

    Any thoughts or anyone with a similar experience?
     
    #1 thisboy47, Jan 25, 2014
    PriFi likes this.
  2. JC91006

    JC91006 Senior Member

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    what enhanced warranty covers this at 134k miles?
     
    #2 JC91006, Jan 25, 2014
  3. cwerdna

    cwerdna Senior Member

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    Water flow valve? Is it is a thermostat?

    What's the part listed on your receipt?
     
    #3 cwerdna, Jan 25, 2014
  4. thisboy47

    thisboy47 Junior Member

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    II
    Coolant flow valve. Part 16670-21010.

    The check engine code was P1121.

    Under warranty until 150k at least here in CA.
     
    #4 thisboy47, Jan 25, 2014
    cwerdna likes this.
  5. Patrick Wong

    Patrick Wong DIY Enthusiast

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    The impact of a failed engine coolant flow valve would include:
    1. The cabin heater may not function very well
    2. The engine may take slightly more time to reach operating temperature since the coolant heat recovery system would not be functioning.

    I would not have expected a failed valve would impact mpg as much as you have noticed. Perhaps some other factor is contributing to the improved results.
     
    #5 Patrick Wong, Jan 25, 2014
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