Fuel Tank Pressure Sensor: Description and Operation

The fuel tank pressure sensor is located on top of the fuel tank. The function of the fuel tank pressure sensor is solely for EVAP leak diagnostics. The fuel tank pressure sensor is a transducer that varies resistance according to changes in fuel tank pressure. The fuel tank pressure sensor works inverse to a MAP sensor. The PCM measures the signal voltage from the fuel tank pressure sensor, which is a reduced value of the PCM 5 volt reference. The signal voltage reads high when the pressure in the fuel tank is low (vacuum) and decreases as the pressure in the tank increases.