19537 4C51 P3081 Engine temperature too low

That DTC is indicative of a missing thermostat, a stuck open thermostat, or a cooling system with 100% antifreeze. It is NOT associated with a defective ECT G62.

When the coolant temperature is too low, that does not necessarily mean a sensor failure. Sounds like the sensor is telling you the truth.

Watch the temperature on the scan tool as the engine warms up. Look for things that keep it from warming up. Things like radiator fans on all the time, straight anti-freeze, stuck open thermostat and so on. That is what it means. It means a system problem, not necessarily a component failure.