CHS Valve premature failure?

Discussion in 'Gen 2 Prius Technical Discussion' started by Spencer Coleman, May 1, 2020.

  1. Spencer Coleman

    Spencer Coleman New Member

    Joined:
    May 1, 2020
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    Location:
    Murray, Utah
    Vehicle:
    2007 Prius
    Model:
    II
    Hay ya'll!

    My vehicle is an 07 Toyota Prius.

    So I just replaced my Coolant Heat Storage (CHS) valve due to a P1116 code and determined that the CHS valve had gone bad. I used the service manual to diagnose it as the CHS temp sensor was within range and also felt for motion when it would recover coolant. I could hear the pump going but it would sound like it was stalling when it tried to recover. I also had made sure my cooling system was properly purged of air.

    I went to O'Reilly's and bought a replacement valve. After installing, purging the cooling system, and taking it on 2 driving cycles (per the maintenance manual) it worked perfectly. Check engine light went out. Code cleared. Pump now now longer sounded like it was stalling.

    Fast forward a week and my check engine light comes back on. Checked the codes. I now had a P1116, P1121, and a P1122. The P1122 code was surprising as it indicated that the computer was reading a low voltage on the valve sensor, which indicated to me that something had failed in the valve again, along with the other 2 codes telling me that coolant was bo longer flowing properly to the CHS.

    After inspecting the engine bay, I noticed coolant puddling and dripping into the belly skirt. After pulling the 2 bolts from the CHS valve where I could see coolant dripping, I noticed that the valve housing has about a 2mm split where the two halves of the body mate where the coolant was dripping out of.

    My question is, has anyone had this issue before? Does anyone know if this is a symptom of another problem? In my years of mechanic work, I've had parts fail, but I'm stumped as to whether or not anyone has had another bad part cause the valve to prematurely fail, or just had this happen before in general :/

    Thanks!
     
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  2. dolj

    dolj Senior Member

    Joined:
    May 14, 2012
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    Location:
    Wellington, New Zealand
    Vehicle:
    2007 Prius
    Model:
    N/A
    A lot of people report problems with generic parts for this, the temp sensor and the inverter coolant pump. It is recommended to buy OEM for these.
     
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