P1121, P1116, Changed Coolant Valve, now Red Triangle

Read this thread: 2007 Prius P1116 code and coolant control valve issues | PriusChat

 

That's not a check engine light that's the Master Warning Light. I wouldn't drive the car far until you pull the codes. The car ain't kidding when it throws that one.

How did you change the valve? Did you duckbill off the hoses or drain the entire coolant?
Where does the coolant look full? Overflow or rad? The overflow is meaningless you must take the plastic cover off and open the rad cap to check the real coolant level.

If you drained the entire coolant it is very difficult to bleed the air. I'm pretty good at it and have a ulift and still struggled when I did mine. The trick is to power cycle on the CHRS thermos as you bleed as air tends to get trapped in the thermos and at the top of the engine. Patrick Wong had a cool get around by pulling the CHRS relay and paper clip jump out the relay 12 volts acorss it to force the thermos to cycle a few times. I missed that on my bleed and it made a bleed difficult.

This car is weird about engine overheat also. Sometimes it throws the master light but no one every reports the true overheat icon which is the thermometer in red.

 

This is a great tool for burping the coolant:



Thanks to Patrick I ordered one of these and it is a huge time saver and coolant saver. It attaches directly to the radiator and holds about 2 pints so you can squeeze the coolant hoses and burp out the air. You can also jump the coolant pump relay and run the coolant pump.

 

Most water pumps seep a small amount through the weep hole. Verify that it is actually leaking. This may be something that can be put off for a while. Keep an eye on the overflow tank and see if you are losing coolant. It may be hard to tell because depending on how well they bled your cooling system it may still burp a few air bubbles over the next week or so.