Cranks but doesn't start after overheating

The car overheated because the engine water pump was going bad. It needs to be replaced before you drive it again. There probably was not anything wrong with the engine coolant temperature sensor. It sounds like you severely overheated the engine.

What is the level of charge in the hybrid vehicle (HV) battery?

Now, the challenge is getting it started.

 

EGR ever cleaned?

 

^ see you’ve disclosed. Still, you’re at 194k now, well into the head gasket danger zone, and the cleaning was late in the day. You did it yourself, everything including intake manifold?

 

P0117 doesn't say "the temp sensor is bad". How would the car's computer be able to know that? P0117 says "the resistance I'm reading of the temp sensor is out-of-range low." The computer can tell you only that; it can't tell you why.

The temp sensor is a negative-temperature-coefficient thermistor—the hotter the coolant, the lower the resistance—and the resistance will be out-of-range low whenever the coolant is 140℃ or more. So if the engine was severely overheating, the sensor and the code could just have been telling the truth.

 

Boroscope inspection of combustion chambers, preferably with cooling system pressurized, can reveal coolant tears making it past head gasket into cylinder, and unusually clean piston tops, the latter again due to coolant getting in.

Also some symptoms: dropping level in engine coolant reservoir, and knock/shake during cold starts, when car has sat overnight.

 

Yes, that is correct.

I do not think so.

A bad water pump probably is not related to your not being able to start the car. I would fix the starting issue with the car before replacing the engine water pump.

I will ask this question again.
What is the level of charge in the hybrid vehicle (HV) battery?

 

The world is full of people whose understanding of car trouble codes never got past "the one-liner next to this code has the words 'temp sensor' in it, so it must be telling me to replace the temp sensor", and a lot of those people work in parts stores or shops.

Word to the wise: every trouble code has a section in the car's Repair Manual specifically about it, and every one of those sections has a box part-way down the page headed "detection condition", and the words in that box tell you exactly what the car's computer has noticed when it sets that code. The code doesn't 'mean' anything more or less than what that box says. (The rest of the section in the manual will be ideas to help you pin down why the computer might have seen what that box says.)

As that box, for P0117, just says "short in engine coolant temperature sensor circuit", that leaves a human to figure out why the computer might have seen a short (very low resistance) there. Usual culprits can be mice chewing the wiring. The sensor itself would be a very unlikely cause: thermistors just don't go bad much.

But seeing further down the page that the possible-short resistance reading would correspond to temps 140℃ or higher, and knowing the engine happened to be severely overheating just then, makes room for the possibility that the sensor and the wiring are all fine, and it was just reading the temp it really saw.

Toyota Service Information and Where To Find It | PriusChat

 

Moral of the story, get your codes from O'Reilly, but do you own diagnostics?