Error Code P1121 - Coolant Flow Control Valve Position Sensor Circuit Stuck

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by YosemitePrius, Mar 16, 2018.

  1. YosemitePrius

    YosemitePrius New Member

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    2007 Prius
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    Base
    Hi Prius friends,

    I have a '07 Toyota Prius base. The check engine light recently came on (not flashing, just solid). After taking it to AutoZone to do a very simplistic and free diagnostic test (Toyota Dealership wants me to pay $140 their diagnostic) the results of this test are an error code of P1121 - "Coolant flow control valve position sensor circuit stuck". I've called one Toyota/Honda mechanics shop that says that they want to do their own Tech Stream diagnostic that they claim is a highly superior diagnostic test that usually cost $100, but they'll do it for $50 (which feels shady to me because shouldn't the price be the price?) Once I asked what the cost of the repair could be he said at least $800. I was shocked and told him that it sounded like BS. He said that cars are a money pit (as if I wasn't aware..) and that the reason the for the price was if they needed to take apart the dash and remove a bunch of parts to get to the sensor (which I don't like when they have to do that because it opens up the possibility of something not being put back together properly and then having more issues). I should also note that I've had this Prius for six years and I've never had anything major go wrong with the exception of replacing the hybrid batteries (but they were under CA mandated warranty and the dealer replaced them for free!) I originally thought this would be an easy fix.. just "unstuck" the sensor... But $800 seems completely unreasonable to me. I've looked on other threads that address this specific error code issue but I haven't found anything related to price. I'm asking if $800 for this repair seems reasonable/unreasonable? Because all of the threads that discuss this make it out like it's no big deal and I can buy the part myself and do the repair myself. Does anyone agree?

    Melissa
     
  2. hchu1

    hchu1 Active Member

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    The coolant control valve is located more or less right behind your driver side headlight, pretty much on top of your inverter coolant pump fyi. It is not particularly difficult replacement, certainly not $800 and not require the removal of the dash. Good, that you didn't fall for the BS, the valve is not high priority for fixing, the check engine light will go off/on intermittently if you leave it alone. Your car will operate fine til you decide to replace it, that is the solution. The part should cost you about $50-75 depending on where you get it. Online is your best bet for least expensive pricing. I can't say how much for labor as I replaced it myself.

    Replacing it sooner will give you peace of mind because whenever the check engine comes on you'll think, is it a p1121 code or some other issue. So, good luck.
     
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  3. JC91006

    JC91006 Senior Member

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    The most expensive Toyota dealer will charge about $500 for this repair
     
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  4. exstudent

    exstudent Senior Member

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    You will have to get it replaced before your next smog check. If the valve is stuck in the wrong position, you may have no cabin heat.

    $75 at Camelback Toyota (Phoenix, AZ). No Sales tax for California. Free ground shipping when $150+ parts order; order some maintenance items: oil filter, engine water pump belt, engine water pump, water pump tensioner bearing, rear brake shoes, front brake pads, coolant (SLLC type needed), crush washers (oil drain plug, transaxle drain plug), etc.
    2007 Toyota Prius Parts - Camelback Toyota Parts - Genuine OEM Parts - Free Shipping

    The sensor is reporting that the 3-way coolant control valve is STUCK. It might unstick by itself one day, but it will stick again. The valve is bad and will get worse over time; permanently stuck in the wrong position. Depending on the position it is stuck, the engine may run more/longer than necessary to warm-up and/or no cabin heat. You may want to time the replacement of this valve when the coolant needs to get drained and filled for the engine and inverter loop.

    Call various dealers and mechanics for replacement of the 3-way coolant control valve:
    1) labor only if you supply parts
    2) their parts and labor price
    3) any discounts for AAA, Costco, dealer coupon, etc.

    Price is what the market will bare. If you don't like it (which was the case for you), move on; the shop will realize they were asking too much. Next victim, they will ask for less.

    Since you live in Yosemite, $800 might be the "fair" market rate. I can't imagine there being that many dealerships and independent shops around, to drive prices down.

    Don't rely on the free code reading from the chain auto parts store and Midas. They are not using Techstream (software approved by Toyota and made specifically for Toyota/Lexus). Consider investing in mini VCI w/ Techstream on Amazon ($22+); you may have to return a few of the cables since pin issues seems to be common. If you have PRIME, free returns. You will just need to get an obsolete Windows 32bit OS laptop. Friends/Family in IT will likely have some obsolete laptops collecting dust; Craigslist is another option. You will now be able to have dealer level diagnostic reading for $22+.

    Perhaps on your next road trip to the bay area, get the valve replaced at Luscious Garage (SF) or Art's Automotive (Berkeley).

    When was the last time the transaxle ATF was drained and filled, if ever?
    Read post #473; ATF fluid changes ARE Required. | Page 24 | PriusChat
     
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  5. SFO

    SFO Senior Member

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    This is generally true for many in CA, but not all counties require a smog check every two (2) years. It could be that Melissa is in one of those counties and can wait until an affordable opportunity presents itself.

    The map is slightly dated : https://www.bar.ca.gov/pdf/Program_Map.pdf
     
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