Red Triangle of Death with temperature warning?

Have you checked the coolant level in 3 places:

1. Engine radiator (remove the cap so you can see inside)
2. Engine coolant overflow reservoir
3. Inverter coolant reservoir

Also, what is the condition of the engine coolant pump and the serpentine belt that spins the pump pulley?

 

You might have a failed inverter pump

I would check your oil level while you're checking your coolant levels

 

The high temp warning on the MFD comes on when the ICE reaches 250F. Fill and bleed the radiator before driving the car anymore. Neither of the repairs you mentioned should have required messing with the engine cooling system but if they did happen to drain it chances are they didn’t get all of the air out.

 

you need a prius aware scanner

 

You got the high temp warning and kept driving? How far? It’s quite possible you cracked the head by overheating the engine. Check your oil to see if it looks funny. Check your coolant for signs of oil also. If your car had a temperature gage and it was in the red would you continue to drive the car? That light is your temperature gage in the red.

 

@mmmitch, did you do this yet? Do not drive your car until you do.

 

2008, Toyota Prius, 270,000 miles, work car. I drive the hell out of my sweet little Prius!! This car is one tough little mambajamba! Sooo, I was taking a break from a job I’m working on because it was 111 degrees on the asphalt! I was sitting in the car with the AC cranked on high for about 15-20 minutes and the car started to do a little shake/sputter, in the engine area, almost as if it was running out of gas, which I was very low on gas. The red triangle came on and the high temperature light came on, so I turned it off for about an hour, finished my job and then started it back up (should have checked fluid first but I was pretty near heat stroke myself!) the red triangle still came back on & so did the high temperature light so I drove to the nearest gas station (qt) for some ethanol free gas. Was there maybe 10 minutes and the car alarm went off by itself, I think (dog and 15mo grandson love my key phobe so it’s a fubar mess) and at the mental state of heat exhaustion that I was in I could have set it off myself) anyway, started it back up all the lights went off and I drove home and it’s running fine 30 miles away ‍♀️ not sure if this info will ever help anyone but I gotten so much of this chat forum for over 3 years now, I thought I would contribute. I have literally save thousands of dollars fixing things myself bc of some of the post here! Thank you to all who contribute (in explicit detail) $$$$ money saved puts food on my table!