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P1150 help

Discussion in 'Gen 2 Prius Technical Discussion' started by e9coupe, Sep 20, 2023.

  1. e9coupe

    e9coupe New Member

    Joined:
    Sep 20, 2023
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    Location:
    Roseville, CA
    Vehicle:
    2005 Prius
    Model:
    Three
    2005 Prius. I just purchased the car after an accident and have no history on it. After doing all the repairs I got the car on the road and it gave me a P1150 code after about five minutes of driving. I'm new to hybrids but not working on cars. After searching for P1150 possible causes I can see that the coolant is flowing and I bled the system for about five minutes and didn't find any noticeable air. I also had the reservoir unmounted with the hoses still connected and it sounds like there's air in the tank, coolant sloshing around. Is this normal?

    My question. When I probe the 2-pin connector for the flow valve I get nothing, no matter what I do with the engine, ignition, cold start, anything. Should I be getting +12v at that connector? I also noticed that both wires have been "probed" in the past with telltale signs of poking through the insulation so I'm assuming this was an ongoing issue.

    I'm guessing that the valve's default position is open (flow) and the valve closes it or restricts it during warm up? Does this explain why even though I"m not getting power to the valve the coolant still flows and gives me the P1150 because it's warming up too slowly?

    I've read the diagnostic PDF for P1150 but wanted to ask about the power to the flow valve first. I also noticed that the PDF shows a 6-pin connector to the flow valve instead a 2-pin like mine. Maybe I'll looking at it wrong.

    I have a temp sensor I can swap on the reservoir and I was going to check ECM output.

    Any help is appreciated.
    Dan
     
    #1 e9coupe, Sep 20, 2023
  2. mr_guy_mann

    mr_guy_mann Senior Member

    Joined:
    Sep 3, 2020
    3,434
    1,493
    0
    Location:
    NJ-USA
    Vehicle:
    2006 Prius
    Model:
    Four
    Hello and welcome to PriusChat!

    The ECM sets P1150 when it doesn't like "something" about the temperature sensor for the Coolant Heat Storage system. The system stores hot coolant in a thermos tank and uses it to warm the engine some on the next cold start.

    There's a CHS pump just behind the tank (not shown in this diagram), the temp sensor on the bottom of the tank, and the "3-way" flow control valve mounted high between the radiator and the inverter. (The flow valve has 3 hoses and 6 wires & is located "next to" the inverter coolant pump). The coolant pumps have 2 wires.


    Diagnosing something like this is much easier if you have a scantool that is capable of showing Prius - specific data from the ECM. TechStream is one option. Here's a thread that reviews several scantool apps and devices. Some can scan all systems for codes and (all) data.

    https://priuschat.com/index.php?posts/3290690


    So I would drive the car - get it hot. Then turn the A/C heater blower OFF and park it. The next morning, turn the car - ignition on (not READY) - no foot on brake and power button x2. Connect your capable scantool and select data for RPM, Engine Coolant Temperature, CHS temperature (tank outlet temp), and water flow control position.

    Now foot on brake, power button x1 and go READY. On a good car, you should hear the CHS pump run for about 5 seconds. CHS and ECT temps should increase from near ambient by around 100°F. Then the ICE should start up.

    Here's a capture of my 2006 - you read the graph from left to right.

    See what your car does in comparison. (At some point you'll want to seal the poked wires - assuming they aren't damaged by corrosion)

    FYI, your first 5 posts are moderated so they can take some time before they appear on the forum. Screenshot_20230323-084851.jpeg IMG_20221118_192203682.jpeg

    Posted via the PriusChat mobile app.
     
    #2 mr_guy_mann, Sep 21, 2023
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