My P1121 Repair

I've posted a few times on this forum, usually questions, which get answered pretty quickly and I've already performed some major repairs myself. Today I wanted to share my experience with repairing the p1121. I had the p1121 engine code come up about a 1 1/2 years ago, just after I got the car from a dealership. I did numerous road trips with it turning on and off so having this code, at least in the Arizona desert doesn't seem to affect much. However, now that inspection is up I couldn't let this go any longer.

Before I begin, I highly recommend reading this thread: P1121 - Coolant Control Valve Replacement (with pics) | PriusChat I'm posting this thread to show some of my own frustrations with this.

There's two routes to repair this issue: Easy and Hard

EASY ROUTE:
1. Drive Car to Mechanic
2. Pay Mechanic 500$

Honestly, this is the hardest repair I've had to do on this car, and I've rebuilt the freaking hybrid battery!

HARD ROUTE:
First the tools:



Harbor Freight Hose Clamps (8$)
Harbor Freight Screwdriver (2$)
Harbor Freight Headlamp (2$)
Dollar-store plastic basin (1$)
Dollar-store plastic funnel (1$)
Duralast Socket Wrenches (20$)
2 Gallons Super Long-Life Coolant (50$ from the dealership)
There are other tools I "used" like the ultra-cheap latex gloves.

Plus: You'll need the part. I ordered it through Amazon. Part # 16670-21010
Plus plus: Set aside 4 hours minimum.

I removed the plastic paneling underneath and removed the panel near the engine.


This "screw" is a lie. It is a push-button. I honestly cannot tell you why Toyota would do this. This is just the tip of the iceberg when it comes to irritants. If you attempt this I encourage you to yell "Akio!" (President of Toyota) instead of the loud swearing you and I both know will occur.

I had to choose between draining the system, which I didn't feel comfortable with, or clamp the hoses. I chose to clamp the hoses but bought 2 gallons of SLLC just in case the clamps fail.

These come in a set of 4 in different sizes. You'll use the 3 biggest ones for this. I read that someone didn't get this to clamp right and had to get two sets. I used 1 set but I had to squeeze the hose into the 2nd smallest. Plus I used the largest one on the bottom. The key to using the large one is to realize that you want to push the hose to the end on the opposite side of the screw part. It's hard to explain, but essentially if the hose slides at all you can have leakage and putting the hose near the screw creates this open area on the other side. I used all four of the clamps. I'll get to how I used the smallest one that doesn't fit in a moment.


I used the smallest hose clamp as make-shift plyers for those metal hose connector rings. That plug on the right is the electrical component. This was one of the hardest thing to get off. It only took about 30 minutes to get the panels off and put the clamps on. It took another 30 minutes to remove this piece. My only advice for this is to bend the metal part it hangs off of so you can get a better look at the tab. I nearly destroyed the plug to get it off, and I honestly thought the metal of the piece would fail before I could get the thing off.

It's important to mark your tubes, You won't really confuse the bottom one but you WILL confuse the two hoses to the left. A single dot was already on my upper hose, which was good enough for me.


A poorly taken shot from under the mess, you'll want to have safety glasses (I used sunglasses) there's a lot of crap that can fly into your eye while you're down there. You can barely see the hose clamp in this image.



I loosened the hose rings with the smallest hose clamp. I don't recommend this but these are so hard to get off that I'm not even sure plyers would work! Be sure to take a photo of your hands before you start the clamping, you'll want a memory of what they used to look like before they get mutilated by your engine block. ("AKIO!!!")


Once the hoses were clamped I unfastened the hoses from the unit and unscrewed the two mounting screws on the right, which were extremely difficult as you can only get about a 1/4 turn on your socket wrench each time. The lower screw was a size 10, the upper was a size 12. Why? I have no idea. Probably some socket-wrench related conspiracy. ("AKIO!!!")

After the unit was freed, I attempted for about 30 minutes to remove the unit. IT IS IMPOSSIBLE TO REMOVE THE UNIT FROM THE TOP! I mean, unless you remove the whole engine block or remove more parts. Instead it HAS to go through the bottom, there is a mess of hoses down there but if you put the lower hose way out of the way you can find a window. I removed the lower hose from the work area, tucked it under the ledge closer to the middle of the car. After I FINALLY got the thing out through the bottom, and put the new one back in. It's important to note that unless your hand has two 4-feet 16-jointed fingers, you'll have to put the lower hose up into the unit from the bottom. Do not scream "Akio!" unless you want residual coolant flowing into your screaming mouth.



I got the hoses back on but I lost a significant amount of coolant as I thought the amount draining was coming from the broken unit when I removed it, only to find that the middle hose was not tight enough. I lost maybe a quart this way. I put it back into the engine after I filtered it and poured it slowly but still managed to spill quite a bit as it was mostly full and the funnel I had didn't provide a good seal and would allow coolant to overflow. I kept pouring in the coolant with my car on max heat to get the engine to cycle. I didn't lose much so hopefully the system would be fine. I didn't do any major bleeding but kept the cap open when the engine was running. I'll keep the coolant around for some time just in case I get another issue in regards to this.

The space is very tight and I cut myself numerous times. Mostly superficial wounds but a few bleeders. It's possible you physically CAN'T do this repair as the space is extremely tight I had to be down to my elbows to get this completed.

The piece with the failed valve you can see is stuck in the open/closed position. Plus you see my hands, which stopped bleeding at this point.

I didn't have a lift, which would have helped tremendously, and I get nervous about working under a car with the jack that comes with the Prius. So I parked it over the sidewalk lip and let the residual coolant flow into what is left of my hair.


Additionally, if you're a Large Nosed Gentleman, like myself, you'll want to get a rhinoplasty or invest in a better lift than the sidewalk, I had to squeeze my face in sideways.

Anyways, that's how I managed to cut up my hands and get covered in coolant...

...I mean, replace my coolant control valve.

 

Thanks! I try to inject humor to make it a little more fun to read. I will listen to the engine. So far it sounds normal, no chugging, bubbles or anything.