Fuel Tank Pressure Sensor

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 the difference in pressure between the fuel vapor inside the fuel tank and the outside air. 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 will read low when the fuel vapor pressure in the fuel tank is low (vacuum) and will increase as the fuel vapor pressure in the fuel tank increases.