Fuel Tank Vapor Pressure Sensor

Fuel Tank Pressure Sensor:

The Fuel Tank Pressure (FTP) Sensor measures the difference between the air pressure (or vacuum) in the fuel tank and the outside air pressure.

The sensor mounts at the top of the fuel tank sending unit. The PCM supplies a 5 volt reference voltage and ground to the sensor. The sensor provides a signal voltage between 0.1-4.9 volts to the PCM. When the air pressure in the fuel tank is equal to the outside air pressure, such as when the fuel fill cap is removed, the output voltage of the sensor will measure 1.3-1.7 volts.

When the air pressure in the tank is 4.5 inches H2O (1.25 kpa), the sensor output voltage should measure 0.5 ± 0.2 volts (1.25 kPa).

The sensor voltage increases to approximately 4.5 volts at 14 inches of H2O (-3.75 kpa).