Coolant sensor

P0118 is a circuit code. It basically says there is an issue in the wiring to that sensor generally not the sensor itself unless it physically broke as the sensor is nothing but a simple resistor that changes with temperature. The fans on all the time and the rev up is normal as the PCM tries to protect the engine because it doesn't know what temperature it is actually at. In your case the sensor has 2 of the thermistors in it. One tells the dash the temperature the other talks to the PCM through the Gray and Black wires. The black is a shared circuit with the oil temperature sensor and you are not showing a code for hot oil so the issue is likely in the gray wire where it runs between the sensor and the PCM. I would start by looking close at the connector and then follow the harness looking for damage.
If you have a scan tool that can read the live data it likely shows the temperature at 40 below. That indicates the sensor isn't connected.
I suspect you will find a wire broken or chewed through or a corroded connector.