P0117 with Normal temp 180 to 195 F

I can somehow tell what happens. Instead of just shutting down, the ecu starts cutting the ICE power gradually. ICE keeps running but instead of sudden shutdown. I know because my prius used to do that on a prolonged uphill drive. Its a 3 gen with 74K Km. Temperature would go to around 100 celsius and the power from ICE would diminish. The electric motor would take over but wouldnt be able to keep up with the hill. I would then stand by roadside, with ICE running waiting for things to cool down. No High temp warning. Then once i got the hint, i removed the ECT at the T joint, started the car and told my son to rev up the ICE. It took around 5 seconds before coolant started coming out. I am assuming that the air was trapped and got removed. I am yet to undertake the uphill ride again...

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Here's me with a turtle prius

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I got the red thermometer light on the dash recently while driving a steady uphill on a highway. Pulled the car over instantly and checked the ECT reading in the Hybrid Assistant app which was at 113 degrees Celsius (see the attached screenshot). It took me a couple seconds before I checked the HA app, so the light might have come on at 110C. The engine would start when pushing the gas pedal. Didn't have the engine shutdown like in the water pump code scenario.

As for the ECT sensors, the HA app must be getting its temp data from the D6 (brown and pink wire) connector. Every time I compared the HA and Car Scanner readings, HA would show the higher temp from the two available in the Car Scanner app.

 

I know the threshold for the EHRS sensor to turn on the light is 120℃ because I actually used a variable resistor in place of the sensor and turned it until the reading was 120℃ and the light came right on like clockwork.

I've just never actually gone out and done the same thing with the ECT sensor. I keep meaning to; I would be more sure of that result than I would be just from saying "the light came on while driving and ECT was X". It's possible I don't know all the reasons the light could have come on.

What did Car Scanner show for the EHRS temperature at that time?

 

Haven't sadly checked that Just popped the hood and turned the heater on to cool the engine down