Fuel Tank Pressure Sensor: Description and Operation
DESCRIPTIONThe fuel tank vapor pressure sensor is similar to the Manifold Absolute Pressure (MAP) sensor. It is used to measure the difference between the air pressure (or vacuum) in the fuel tank and the outside air pressure.
OPERATION
The ECM supplies a 5 volt reference and a ground to the sensor and the sensor sends a voltage signal between 0.1 and 4.9 volts back to the ECM. When the air pressure in the fuel tank is equal to the outside air pressure, as when the fuel cap is removed, the output voltage of the sensor will be from 2.0 to 2.5 volts.