Car Problem Reports

Toyota Prius Check Engine Light Due to Failed Three Way Coolant Control Valve

Toyota Prius Problem
94 Reports
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Model Years Affected: 2004, 2005, 2006, 2007, 2008, 2009

Engine Affected: 1.5L 4 Cylinder

Average Mileage: 97,323 mi (33,000 mi - 226,200 mi)


The Check Engine Light may illuminate with a fault code P1121 stored. It is commonly caused by a failed three way coolant control valve. Valve replacement is recommended if this occurs.

  • Visitor, , 109,000 mi

    Engine light goes on intermittently...went to AutoZone and pulled a P1121 code (coolant control valve). Went to Toyota dealer where I purchased car to get repair estimate. They said I needed to pay $120+ for the code (which I got free)to replace coolant control valve was 3 hours labor (Toyota tech manual says 2.1 hrs) and part was $78.00 plus a very expensive coolant total replace...(I read that the valve can be replaced without loss of any significant amount of coolant) I checked internet and found that low coolant level may also generate a P1121 engine light...Ergo I checked my coolant level and found it to be very low...I added coolant and light went off. So far so good...if light comes on again I will report it.
    Warning: Toyota dealers are, in my estimation, liars and thieves.

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  • Visitor, , 140,000 mi

    I have a 2007 Toyota Prius w/140,000 miles. I took my car in because I rec'd a recall notice for the water pump, so they replaced that for free. Two weeks later, the "check engine" light came on (I sometimes wonder if the dealership "sabotages" the car to create more business. I know for a FACT that on 2 separate occasions, my car was damaged and the dealership tried to charge me to get the issue fixed. Both times I was able to get the issue fixed for free by being persistent.) Back to the "check engine" light…so I called, and they said it is $110 to get the code diagnosed. I went somewhere else and the guy did it for free. Code was P1121 (coolant control valve). I called Toyota and they said I'd still have to have THEIR mechanics diagnose the problem, because it
    "wasn't as simple as just reading the code, there's a lot more that goes into figuring out what the problem is". I went on a road trip (San Diego--> Portland, OR--> San Diego), totally waiting for my car to blow up or something, because the "check engine" light was on the whole time. Came back, parked, turned car on, and the entire dashboard lit up like a Christmas Tree, including the Big Red Light that means "DON'T DRIVE YOUR CAR!". Took car to dealership, they indicated multiple system failure, including….Coolant Control Valve AND the HYBRID BATTERY! Well, praise my Lucky Stars, Toyota now has a Warranty Enhancement, so both of these issues are COVERED FOR FREE until 150,000 (I have 140K on my car) or 10 years, whichever comes first!
    I'm wondering if the Coolant Valve Issue led to the Battery Failure? Does anyone know?
    Thanks, and Good Luck to everyone w/these issues!

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  • Visitor, , 54,556 mi

    Check Engine light came on and a Florida Toyota dealer's mechanic diagnosed a "failing" water coolant control valve. Dealer wants $550 to replace. I intend to speak with Toyota customer care.

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  • Visitor, , 75,000 mi

    Last year i had the recall on the water pump toyota replaced it but the check engine light came back on about two weeks later the ran diagnostic and told me the system may have air bubble in it and would probable purge itself now my check engine light has been on for several months. Took the car a total of three times. It is that P1121 coolant flow valve. I had that diagnosed for free at Midas with the same codes. Yet dealership said they were wrong when I picked up the car it had the same codes as Midas had given but charged me 95.00 to tell me that. This very same thing happened to my sister in a different state her dealership replaced the water pump again and she has had not problems since. I was informed that this p1121 is directly related to the water pump not being replaced right????? At this point I don't really believe they replaced the pump at which has only compounded the problem. Is the information I recieved about valve and water pump related?????? I need better answers then what I am getting. Thank You for your time.

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  • Visitor, , 38,000 mi

    The check engine light came on for a day then went off. One week later it did the same thing. We had been noticing a little whirring noise from the car (from the driver side dash) in the past few weeks. Took to the dealer and was told the code was p1121 and the cost to replace the coolant control valve would be over $400. I told them that I would call and complain to Toyota Motor Corp to see if they will still cover it because this problem should not be happening so soon (just out of warranty). I looked up the info on this site and saw that the valve issue was supposedly solved and fixed with the 2007 model). Anyway, my service guy went to higher ups and they decided to fix it for free (maybe because I bought my car there and service it there all the time). I am thankful it was fixed quickly by my dealer! BTW, I am a woman.

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  • Visitor, , 170,000 mi

    Our Engine light has gone on and off for about 2 years now. It showed up as a Failed Three Way Coolant Control Valve at a free evaluation, but after reading other reports on this site I wasn't stressing out about it. Finally one day about 6 weeks ago my entire dash lite up with the warning not to drive my car and take it directly to the dealer. We did so and discovered that one of the cells in the hybrid battery had gone out in addition to the Coolant Control Valve. Nalley Toyota replaced the hybrid battery with a brand new 2014 battery free of charge and also fixed the Valve which we paid $300+ for which sounds like less than most others paid for the repair. I'm wondering if the bad Valve leads to the failure of the hybrid battery and it may eventually come out as a recall since Toyota was so nice about the whole thing!

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  • Visitor, , 1.5L 4 Cylinder, 65,314 mi

    The check engine light came on. I took it to my local Toyota dealer and was told it was the coolant control valve. The charge for this would be just under $400.00 to fix. Am taking it to another shop for a second opinion/cost.

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  •  Rookie

    Check Engine Light lit up. I had it read by a mechanic for free - P1121 - Coolant Control Valve. He reset it and within 15 miles it lit up again. At the dealer I'm told it's not under warranty (how's that? It's part of the engine system) and it would be $400 to fix. Dealer service rep said he will ask if they can work with me on this since the car has so few miles on it (and I know that a TSB has been issued against this part) and reduce the cost by about 50%. We shall see...very upset and will contact Toyota to register a complaint about this.

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  • Visitor, , 56,000 mi

    This just happened to me two weeks after the Toyota dealership replaced my water pump due to a recall issue.

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  • Visitor, , 92,600 mi

    Had to replace the coolant control valve per my mechanic. Just had the water pump replaced 30 days ago.

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