Fuel Temperature Sensor: Operation

An negative temperature coefficient (NTC) resistor integrated in the fuel temperature sensor alters it's electrical resistance in line with the fuel temperature (the resistance drops as the temperature rises). The ECM uses this reading to calculate optimum engine performance under all driving conditions. If the fuel is to warm, the rail pressure in the system is lowered. The controlled quantity of the fuel rail pressure solenoid is reduced and the fuel temperature is lowered. See Figure.