Overtemp indication light staying on

[Realtor2015]

I bought a 2016 Prius 4 several months  ago, the overtemp light has always been on since I bought it. I comes on when you start the car and stays on. I have put over 8000 miles on the car since I bought it.  It just came to my attention that the light should not be on(just got around to reading the owners manual)So I replaced the temp sensor- still same issue.  Any suggestions what may be causing this?

[Konrad C]

Have you had the car diagnostics checked? Take the car to someone with experience or even the dealers. If you have your own diagnostics, it needs to be something like Toyota Techstream, where can pay to use a session for the official version! 
Diagnostic will also give you live data, so you will know if everything is operating within spec. 

[QuantumFireball]

OBD-II bluetooth scanner and the Hybrid Assistant app will show you the various temperature readings, you don't need Techstream or fancy stuff for that.

There are four main temperature readings - engine coolant, inverter coolant, motor-generator, and HV Battery (well, there are multiple Battery sensors). I don't know which are tied to the high temperature warning light - possibly all of them? Which temperature sensor did you replace?