P1121 & B1421 w/ photos attached. 1-2 weeks after Inverter Pump Rplcmnt

The solar sensor, did you diagnose in a garage or carport? If yes to both, that can set it off, non issue, ignore. It's not sensing any sunlight.

The coolant control valve is not critical, in the sense of immediate action. I replaced my unit about 2 months ago, after it had lit my check engine light numerous times over the course of 6-8 months. The cel light will go off and on until you replace it. For peace of mind replace sooner than later. When that cel light comes on you never know if it is something really important or just that old cc valve playing hide and seek with you.

As far as additional coolant, your mechanic will just pinch the lines, if he is careful he shouldn't loose more than a couple of tablespoonfuls.

 

I don't recall the 2 having an issue related in such a way. I think that the age of the valve is the issue. The valve is just that, it opens and closes, not constantly like a pump motor. The valve usually gets stuck partially open and sets the cel.

 

The inverter coolant loop and the engine coolant loop are two separate, sealed circuits. The inverter pump job won't have affected the coolant level in your engine (3-way valve) loop, assuming mechanic competence. The fact that yours, or anyone else's 3-way valve failed following inverter pump failure is coincidental in timing but unrelated.

Although the Mishimoto may be a quality product, I'd stick strictly to Toyota SLLC in any Toyota coolant loop. As hchu1 states, the valves stick partially open and are pretty much a guaranteed failure at some point in any Gen 2 Prius' life cycle.

 

A solid CEL is usually an emissions related error, bad for the environment but usually safe to drive

 

In my opinion, the main risk of driving with the MIL illuminated is the failure to see a new code. For P1121, sometimes you may not get cabin heat, but I can hear you chuckling about that right now.

I agree there's no connection with the inverter pump.

 

Agree with JC and andrewclaus entirely.

The only real issue with never replacing the 3-way valve may or may not be passing state inspection, depending on state. It won't hurt the car and a no heat episode can typically be rectified by powering the car off and then readying again. Ask me how I know....although I only procrastinated the repair for about 6 months.

 

You should check your radiator fluid level when the car's cool. It may be low.

Also sometimes with a CEL going on and off, it's a symptom of a failing catalytic converter

 

The freeze frames you have are specific to your p1121 code. You should do a complete health check and then see what codes are present.

 

Yes, that's usually on the first screen when you run the program.

 

[QUOTE="Blackwing, post: 2556601, member: 154064]...Does that not mess with the coolant flow throughout the car?[/QUOTE]

No, it does not. The coolant heat recovery system is a "side arm" off the engine coolant system. All it does is pump a liter or two of hot water through the throttle body and engine block before starting. It hardly seems worth the trouble when you need to fix it.

 

The reservoir looks empty. The plastic cap just pulls off, no unscrewing necessary.

Also check the fluid level in the radiator, since the overflow reservoir is empty.