P1121 - Coolant Control Valve Replacement (with pics)

What's your thoughts on clearing the codes and waiting for the code to come back? To be honest, I've got no idea what the purpose of this coolant valve is. Am I at risk off my engine running hot?

 

Nice write up! I am going to print it out and stick it in my big book of Prius.! Thanks +!

 

Well I cleared the C.E.L. yesterday, went on a coulpe short errans (15 mins & 20 mins), and the C.E.L. didn't come on. I'm going to standby replacing it till the light comes back on again.

Resetting the auto up/down on the window switch was easy.

 

FWIW, my 2008 Prius w/just over 60k miles had the P1121 come on over the weekend.

Dealer (Toyota Carlsbad) quoted me ~$300 + diagnostic fee ($100), but for some reason quoted me for a different valve related to the hot-storage tank (which is supposedly another common repair in the same area) so ended up costing closer to $500 despite me giving them the trouble code.

Not happy with the misunderstanding since I would have done it myself if I knew it was going to be over $400 originally and save $300+ but at least the car is working fine now.

When the light was on there was a rapid whirring sound which sounded like an actuator spinning and stopping audible when the car was stopped - probably the coolant control valve trying to free itself or something - the car had been doing that on and off again for some time with no apparent ill effects. And of course, on the way to the dealer to drop it off the CEL went off and was not making the noise.

 

I've seen the question asked a couple of times, but didn't see a definitive answer...wouldn't/shouldn't this be covered by the Toyota Care Platinum Extended Warranty? Has anyone successfully had it replaced under warranty?

 

My coolant flow control valve was just replaced under warranty - 2009 Prius with 14,000 miles. The car had been making a strange pumping noise intermittently for the past several months and the dealership spent a fair amount of time to find the problem. The engine also ran frequently without charging the batteries. I'm not sure if that was related, but the car seems to run far better now.

 

I know it has been a while but is the coolant for the inverter separate than the coolant for the engine? Do they mix? I have to replace my coolant control valve due to the code I read. I just had the water pump replaced under warranty and had fluid replaced. So my question is should I replace coolant in the inverter loop or it it the same coolant that was just replaced?

 

No mixing, completely separate loops. No need to replace inverter fluid if it is still looking clean.

 

Does anyone know what the warranty coverage is on the coolant flow control valve? Just had mine replaced at a Toyota dealership for about $500. I own an '08 Prius.

 

I'm pretty sure it is 6 years or 60K miles, whichever comes first.
It is 3 years/36K miles. $500 is a pretty high price. I replace them for about half of that.

 

Hey Stomper88,

Thanks for the thorough write-up. It was very helpful. I did the replacement on my '05 yesterday. Thus far it appears to be successful. I'd like to just share some thoughts of my experience on the repair.

First, a little background. I'm planning to bring my car in next week for the steering column and water pump recalls, so I thought that I could tackle the valve replacement even with the discussion of how to properly replace the coolant. The dealer quoted $125 for the diagnostics and $530 for the valve replacement ($79 for the valve, $25 for 1 gallon of the super long life coolant). This outrageous cost obviously influenced my decision. One tidbit for those in California, the valve is covered for 10yrs/150k miles because of some CA emission regulation. This didn't help me since I have 152k miles on my car... (great timing... stupid valve).

Okay, now my observations:
First off, Stomper88's recommendation of the cable pliers is a good one. The clip unclamping proved to be a very frustrating part of this repair.

I used some locking pliers to clamp the tubing with limited success. A substantial amount of coolant leaked out. So if one plans to clamp the tubing, invest in some tube clamps.

Due to the confined space around the valve, detaching the tubing was quite difficult, made more difficult by the need to hold the clamps open with pliers (and the bulky locking pliers holding the tubing mostly shut). It took a couple of hours of grunting and sweating to get all three tubes off the valve. This is where Stomper88's suggestion will likely help a lot.

Putting the new valve in is much easier than removing the old one. Plug and play.

Despite having clamped the tubes, I managed to lose a lot of coolant. So I just added new coolant to the radiator and followed the suggested procedure of warming up and cooling off the coolant a couple of times, topping off the coolant each time.

In all it took about 4 hours for the repair. So all in all a rather challenging repair that could have been easier with the proper tools.

Thanks again for the discussion. Hopefully there won't be any major repairs in the near future.

Cheers,
ChewyT

 

I just ran a diagnostic on my car and got the P1121 error code. However, my need service light keeps going off, then coming back on, then going off, etc. Anyone else's doing this? My car isn't making any strange noises or acting/driving differently. I'm wondering if it could just be the sensors instead of the actual part.

Thoughts?

 

It is likely getting stuck and freeing up causing your light to turn on and off.

 

Thanks for posting this. I was planning to do this with help of a friend but he can't find time due to work and tours. Took both the valve and coolant to Inman Auto Care in Colonia, NJ and they did it for $180. Total cost $273 including tax.

 

I just went to an auto parts store (due to the CEL in my 07') and the codes were p1116 and p1121... Should i follow the same process? or would you recommend something a little simpler? Im just an average DIYer... but as long as its not too complicated Id feel comfortable working on my car.

 

Just replaced my coolant control valve, but the CEL keeps coming back on with the same P1121 code. Lost a fair bit of coolant, recovered most of it, but have not been able to get it back in. I guess I need to bleed the system, but would that cause the P1121 code, or a different one?

UPDATE: Eventually got all the coolant back in, but the code still kept coming back. I don't think the new valve is bad, since I now have heat again (and didn't since the code first appeared). It was due for coolant replacement anyway, so I just had that done at the dealer (since I was not confident about properly bleeding the inverter after all the trouble I'd had with the ICE). So at this point, I'm pretty sure that both systems are properly filled and bled and that coolant is flowing everywhere it is supposed to. Yet the P1121 code still reared its ugly head once again upon my return from the dealership. No warning lights came on during my drive home (~ 10 miles). Engine not running hot. Checked both reservoirs and they look fine.

 

Hello,

I need help. I got the P1121 code on my 2007 Prius. I bought the Coolant Control Valve and replaced it. While I was replacing the valve and I lost about 2 quarts of coolant from the hoses. I did not want to replace the coolant, I just wanted to refill the 2 quart of coolant that was lost.

I think I have a problem because I can only fill about 1/2 quart to the coolant reservoir and my heater is not hot when I set it to 85 degree or HI. It's blowing cold air (while engine is running quite sometime).

Need your advice, what should I do?

Thank you,

 

Lots of info online here on PC about filling of the coolant system. Basically you have to keep adding the coolant to the radiator and cycling the engine until it won't take any more coolant. From what I have read, it takes several cycles to get all the air out. Make sure the overflow bottle is full every time you check or add fluid. Remove radiator cap when cold, fill to top of neck. Put cap back on. Then warm up the engine in "Inspection Mode". Remember don't drive in Inspection Mode as the transaxle can be damaged. It is also suggested to run heater at HI setting with fan on full force. It is also suggested to squeeze the radiator hoses when filling to help get air pockets out.

It is not a one shot thing, but takes a few cooling, heating cycles to get all of the air out. I haven't done this job, but have read quite a bit about it. There are details here on PC. Do a Google search and you should be able to find more info.

Don't forget to use the Toyota SLLC fluid. It is premixed, no need to add water. (Toyota Super Long Life Coolant)

Also please read post #6 that Patrick Wong posted in the following link. It covers what you are doing very well in terms anyone can understand.

Changing engine coolant | PriusChat

Here's a video on how to get into Inspection Mode.

Best of luck to you and I hope this helps you.