Check Engine Light With Code P1121 on Toyota Prius

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.

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Average mileage: 99,483 (33,000–226,200)
Engine affected: 1.5L 4 Cylinder
7 model years affected: 2004, 2005, 2006, 2007, more2008, 2009, 2010
111 people reported this problem
79 people shared problem details
2005 Toyota Prius109,000
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.
2007 Toyota Prius140,000
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!
2009 Toyota Prius54,556
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.
2007 Toyota Prius75,000
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.
2007 Toyota Prius170,000
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!
2009 Toyota Prius38,000
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.
2007 Toyota Prius92,600
Had to replace the coolant control valve per my mechanic. Just had the water pump replaced 30 days ago.
2007 Toyota Prius- 1.5L 4 Cylinder65,314
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.
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.
2008 Toyota Prius56,000
This just happened to me two weeks after the Toyota dealership replaced my water pump due to a recall issue.
2008 Toyota Prius116,000
The check engine light came on intermittantly at first then continuously. Dealer engine analyzer diagnosed the problem. Recommended replacement of the valve.
2008 Toyota Prius- 1.5L 4 Cylinder60,000
Intermittent Check Engine Light with Code P1121
2004 Toyota Prius95,000
Ok, so that code can read accelerator pedal issue or whatever, I found out that is a generic code and is an incorrect diagnosis for the Prius. The correct diagnosis is a valve malfunction. Toyota has issued a service bullitan reporting that this particular valve has known issues and the quoted labor repair time is 2.1 hours. The part itself is apx 80 bucks. Just FYI.
2006 Toyota Prius114,860
Check engine light on and off by itself. Code P1121, and dealer said it's coolant control issue, ask for $500 to fix it. And last time, they added, there's water pump issue too, another $500, what??!!!
Check engine light goes on and off with code P1121. Have had 2 new water pumps installed (both on recall or warranty), last one one year ago. Dealer says replace coolant control valve, $700. Is this related to the water pump issues??? Thanks! My other mechanic thought the code is for an accelerator pedal performance problem. Any ideas??
Check engine light came on and since it was due an oil change, I had that done promptly. When the check engine light continued to stay on, I took it to the Toyota dealer who told me it was the 3 way valve and it would cost $450.00 for the repair. Since the car had 44,700 miles, and was out of warranty by 9,000 miles, I had no choice but to foot the bill. It appears that Toyota knows they have a problem but are reluctant to fix it. The new recall for replacement of the water pump is also a little late. I had to have a new water pump installed at 32,000 miles when the car was still under warranty, and now they are going to replace it again. Only when they get many complaints do they do a recall.
2007 Toyota Prius221,925
Same problem error code P1221. Toyota dealer charged $60.00 for the first computer scan. Then called me and told me that they need to do some pinpoint scan to determine the issue even more. The total cost to scan $220.00! Finaly told me that it was the coolant control vavle which would cost $500.00 to fix. Not fixing it right now.
got the 1121 and 1116 codes related to my check engine light being on. It's been on for the last 100,000 miles so I'm not sweating the engine blowing up. but now I can pass my smog test because the engine light is on. I don't want to go to the dealer they always find stuff they need to "fix" and iit seems it always costs about $1000. Any suggestions? Can I replace the coolant control value my self?
2008 Toyota Prius160,000
Check engine light came on, driving on highway during normal commute. Next day the engine light was off, but took it to shop and they came up with the 3 way valve error code. Believe the scan further said sensing circuit was 'stuck'. Independent shop repaired for about $240 plus tax. They replaced the whole unit.
2007 Toyota Prius135,000
Check engine warning light on
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