P1121 - just assume coolant control valve?

I'm impressed with how quick you figured out the right answer to p1121. You probably know way more about cars than you give yourself credit for. And yes a 2009 w/85K is my dream car... I could get so much life out of that!

Do you have a friend or family member that can work with you on this stuff? For example fixing the p1121 is only a $42 part: https://www.ebay.com/itm/394097566363 and if had someone with a little experience with hoses and a bunch of hose clamps to coach you up you could fix this yourself in a couple hours for the cost of the part. Whereas if you were dependent on a hybrid shop you'd be looking at $600 instead.

As in what's your budget like for when issues like hybrid battery and brake booster pump come up? As long as you have the budget/plan for that, then this Prius will be insanely reliable for you.

 

Yes replace the coolant control valve You can even kind of hear it making noise and whatnot at times many times with this system and in this car with that code just replace it and be done with it or you can spend the afternoon running the diagnostics and playing around only to change that valve anyway $42 is really not throwing parts at anything It's a near 100,000 mile part and many years old and a known issue.

 

While there is always the possibility that the car has a problem with wiring or a connection, I have not seen or read about any Gen2 Prius that P1121 wasn't the coolant valve.

Most here recommend using a Toyota part as most reliable. AfterMarket parts are less $$ but can fail sooner.

Posted via the PriusChat mobile app.

 

Also, it's worth mentioning that many people go years and years ignoring this problem without much consequence other than loss of MPG. And I'm not saying that's the right option, but it is an option.

 

If the OP chooses to fix this, one of these:

Astro Pneumatic 9409A Hose Clamp Pliers | JB Tools

will come in handy. It doesn't have to be specifically that one. Spacing is really tight and the usual sort of "put a big pair of pliers on the clamp" approach won't work.

My son helped me with this, and even so, it was kind of a PITA. We ended up releasing two of the three hoses to the 3 way valve at the end away from the valve because there just wasn't enough room to easily put them on with the valve in place. That is, old one out with those two hoses, transfer the hoses to the new one in exactly the same orientation, and then install the new one. One of the hoses has easy access, that one was released at the valve and later reattached when the new valve was in place. Even with the inverter cranked up and wedged with a 2x4 getting the valve out the top was really hard. We ended up taking it out and putting it back in from the bottom.

There is a long thread about this issue, read the whole thing before trying it yourself.

P1121 - Coolant Control Valve Replacement (with pics) | PriusChat