Fuel Tank Pressure Sensor

The fuel tank pressure sensor is used for certain EVAP system performance tests performed by the ECM. The fuel tank pressure sensor contains a diaphragm which changes the resistance based on pressure. When EVAP system pressure is low, during purge, sensor output voltage is low. When the system pressure is high, the sensor output voltage is high. The ECM monitors the pressure changes within the system by using the fuel tank pressure sensor signal. This information can be used in order to detect any leaks within the system or to verify the operation of the system components.