W 3500 L4-5.2L DSL Turbo (2006)
Fuel Temperature Sensor: Description and Operation
Fuel Temperature (FT) Sensor
The fuel temperature (FT) sensor is installed on the fuel supply pump. It is a variable resistor. The FT sensor has a signal circuit and a low reference
circuit. The FT sensor measures the fuel temperature of the fuel. The engine control module (ECM) supplies 5 volts to the FT signal circuit and a ground
for the FT low reference circuit. When the FT sensor is cold, the sensor resistance is high. When the air temperature increases, the sensor resistance
decreases. With high sensor resistance, the ECM detects a high voltage on the FT signal circuit. With lower sensor resistance, the ECM detects a lower
voltage on the FT signal circuit.
