My P1121 Repair

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by Armicron, Apr 17, 2016.

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  1. Armicron

    Armicron Junior Member

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    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:

    DSC00595.JPG

    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.
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    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.
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    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.

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    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.

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    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.

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    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!!!")

    DSC00609.JPG
    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.

    DSC00611.JPG

    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.
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    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.
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    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.

    DSC00605.JPG
    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.
     
    #1 Armicron, Apr 17, 2016
    Last edited: Apr 17, 2016
  2. bisco

    bisco cookie crumbler

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    congrats, well done! great write up and pics, thanks!(y)
     
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  3. andrewclaus

    andrewclaus Active Member

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    Nice write-up. I like your self-deprecating humor.

    I have a strong plumbing background, so I didn't attempt to to clamp the hoses--I know it's hard to make that work. The coolant refill didn't daunt me and I wanted a Mini VCI for other projects anyway and that made it simple. And my coolant was due for change in less than a year anyway.

    A pair of 12" long needle nose pliers was the perfect tool to remove the hose clamps. That part of the job took minutes for me. Wrench time was less than an hour (hardest task was the splash guards). Refill took hours, mainly doing something else waiting for cool-down. I had to top off again the next morning.

    You'll want to keep a close eye, and ear, on your cooling system in the coming days. Listen for turbulence in your heater core, and funny sounds coming from the CHRS pump (cavitation) on cold starts. Check radiator level every morning for several days. (I found I could do that by only removing two of the six pesky fasteners on the splash guard.) If you have problems getting it 100% full, use a flex hose at the upper radiator bleeder--that's real easy and cuts down on the mess.
     
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  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Nice work under adverse conditions. A few suggestions for others who may attempt this task in the future:

    1. Exert upwards force on the large black plastic panel covering the radiator, while rotating each plastic fastener with a Philips screwdriver, which allows the fastener to pop out of the hole. Don't be surprised if one or more of the six fasteners break, the plastic gets brittle with age. Replace broken fasteners at your local Toyota dealer's parts counter or buy a supply online.

    2. Use the yellow Lisle plastic funnel when filling the engine coolant system. That makes it much easier to get air out of the system.


    3. Do not be afraid to drain and replace the engine coolant. The drain valve at the coolant heat recovery canister (hidden in the driver's front fender well) will remove ~95% of the coolant that can be drained, then you don't need to open the radiator drain cock or find the engine block drain. Run the CHRS system pump using Mini VCI or my approach of shorting the switched CHRS relay terminals - look for my post on that subject.

    4. It would be best to raise up the front of the car on jack stands so that you don't run the risk of injury to your face as the OP depicted in his last photo.
     
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  5. Armicron

    Armicron Junior Member

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    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.
     
  6. Mark 30187

    Mark 30187 Junior Member

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    it is easier to remove if you remove the head light out first it only takes a couple screws 5 bolts and its out and you dont have to fight anything
     
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  7. ILuvMyPriusToo

    ILuvMyPriusToo Senior Member

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    Nice story and pictures - thanks for adding all that to the forum!

    @Mark 30187 , to clarify, pulling the headlight lets you remove the valve from above?
     
  8. priusenvy

    priusenvy Senior Member

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    Pulling the headlight lets you take the valve out the side through an opening normally blocked by the headlight. I did this and it was actually pretty easy to get the valve out - no struggle at all really. Didn't have that much trouble reattaching the lower hose with the access available with the headlight out either.
     
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