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Finding CHRS relay

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Weinerneck, Nov 7, 2009.

  1. Weinerneck

    Weinerneck New Member

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    I have a P1121, control valve stuck code. I bought the control valve and am ready to replace it. I read Patrick's post on forcing the pump to run by jumping the terminals of the CHRS relay. Found the relay box on the firewall but none are noted as "CHRS". There is one that is close listed like this;

    CHS
    W/P

    Is this the CHRS relay?

    Others listed on the cover that I have are;

    PS
    HTR

    PTC
    HTR
    1

    PTC
    HTR
    2

    Thanks for your help,
    Bill

    05 Prius - 127,000 miles
     
    #1 Weinerneck, Nov 7, 2009
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Bill,

    The CHS W/P (coolant heat recovery system water pump) relay is the one that you want.
     
    #2 Patrick Wong, Nov 7, 2009
    2 people like this.
  3. Weinerneck

    Weinerneck New Member

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    Re: P1121, Control Valve replaced

    Replaced the control valve today and everything went pretty good. I used Patrick Wong's way of jumping the CHRS relay to run the pump and had know problem getting the air out. I ended up not draining the cooling system, clamped off the three hose's going to the valve and then replaced the valve. Did it mostly from the top side and didn't remove the engine under cover, a little tight but saved the hassle of removing the cover.

    Took it to a friends house, cleared the codes, and all is good thanks to the help from this site and people like Patrick.

    Thanks again,
    Bill
     
    #3 Weinerneck, Nov 8, 2009
  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Re: P1121, Control Valve replaced

    Hi Bill,

    Good to hear that your project was successful.

    Have the engine and inverter coolants been replaced yet? If not, that is past-due.
     
    #4 Patrick Wong, Nov 8, 2009
  5. Weinerneck

    Weinerneck New Member

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    Re: Coolant change

    No they haven't and I was thinking that it probably should be done. Is it as simple as pulling the plugs, draining the old and replacing with new? Or should I take it in and have it flushed, I saw there was a lot of hoses going every which way under the hood.

    Bill
     
    #5 Weinerneck, Nov 10, 2009
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Bill,

    The engine coolant replacement is not simple: you need to find and open the three drains (CHRS canister, radiator, and engine block). Measure the amount of drained coolant so you know how much to replace. I've posted previously on the details. I don't think there's a need to have the system flushed unless you see debris in the drained coolant.

    The inverter coolant replacement is easier, but you still need to measure what was drained out, and get air out of the system. Note the bleed valve. Success is attained when you don't hear air bubbles while the inverter coolant pump is running, you see turbulence in the inverter coolant reservoir, and you've replenished the coolant volume that had been drained.
     
    #6 Patrick Wong, Nov 10, 2009
  7. Weinerneck

    Weinerneck New Member

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    Patrick,

    Did the Inverter coolant today. It was pretty straight forward and I had it done in no time. Have to pick up some more SLLC to do the engine this week. Luckily the weather has been unseasonably mild and is going to stay like this for at least a week.

    Bill
     
    #7 Weinerneck, Nov 14, 2009
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