Check engine light on Valve to the coolant pump failed. Is it right?

Sounds similar to this:

http://priuschat.com/forums/gen-ii-...ybrid-system-coolant-valve-warranty-help.html

You can ask the dealer for the DTC codes and do some research.

 

There is TSB (EG001-08) describing this known periodic problem in 2004 Prii. The new valve is an improved model and the code registered is P1121. It is covered under the 36/36,000 drive train warranty and my dealer (CT) quoted $300 for the repair.

The MFD can be repaired inexpensively, but NOT by a dealer. There is a TSB on this problem as well as it is due to a manufacturing defect in early 2004/2005 MFDs. Do a search for Prius MFD Failure and you will find a full description of the necessary repair procedure that can be done by any experienced electronics technician.

JeffD

 

Crap. Now I just got the p1121 error code. I was able to find the technical service bulletin but can't seem to post an external link because I'm newbie here. I found it pretty fast, so you should be able to do so as well by searching terms 'prius p1121'.


The steps to install sound fairly easy to do, but was wondering if anyone has done this. I found the below thread which mentions the part costing around $70, but the link to that web site is bad.
..forums/gen-ii-prius-technical-discussion/39624-coolant-flow-control-valve-air-heating-issue.html

In any case, if anyone has installed this themselves, please give me a holler. If I can figure it out and do it myself, I will definitely post pictures of each step for everyone else.

Thanks.

 

Odd... on obd-codes.com, it lists this for toyota code:

P1121​

Accelerator Pedal Position Sensor Range/Performance Problem.

 

Generic interpretations of Prius DTC often are incorrect. DTC P1121 is "Coolant Flow Control Valve Position Sensor Circuit Stuck".

There are three possible reasons for this DTC. Either the valve is bad, or the cooling system is clogged, or the engine ECU has failed.

 

Well, I did it! I replaced the coolant flow control valve myself, and it was pretty simple. I thought I took more pictures than I did, but I do have some. You can look in my photo album on this site labeled 'sclieu'.

Basically, I got a prius maintenance book, and follow the directions to get to the coolant heat storage tank, since there were no directions to replace the coolant flow control valve.

General steps (make sure your car's been idle for a long time, since the coolant may still be hot in the heat storage tank):
1) remove plastic covering to get to radiator
2) jack car up from the front driver side.
3) remove plastics to get into the front driver wheel well.
4) drain radiator
5) drain coolant heat storage tank

The coolant flow control valve only has 3 radiator hoses to it, and I think 3 bolts attaching it to the car frame. Luckily, my hands are pretty small, and I was able to get to the radiator hoses and bolts w/o having to remove anything else. However, if you have very big hands, you may have a difficult time getting to it.

Just disconnect everything to the coolant flow control valve, and then repeat everything backwards to put it back on. I think I got to the two radiator hoses to the valve from the top of the car, and the last one from the bottom of the car.

The book says to be very careful adding the coolant back in as the prius tend to store large air pockets due to the way the lines are routed, and this will damage your engine if coolant is not flowing properly when the car is hot. Folks on this forum suggest to keep track of how much coolant comes out so that you can add the same amount.

I did not have any tools to do this as the book suggests, but was able to get most/all of the air pockets out manually by:
1) slowly adding coolant and squeezing the radiator hoses to get the air out.
2) start car, rev engine, let pressure build up, and then use an allen wrench to release a valve near the upper right (driver) side of the radiator.

I did this a number of times and was able to get more coolant in. Fortunately for me, seems like the prius computer reset the error code so I didn't even have to go get the check engine light reset.

I drove the car for about a week, and I constantly let more air out using the allen wrench after each long drive, and have not had any problems since.

If someone needs more details, let me know.

Thanks for everyone's help.

 

I am replacing my coolant control valve and need more details on how to refill the coolant back into the storage heat tank. Can u please tell me step by step on how to do that?
Thanks