Fuel Tank Pressure Sensor: Description and Operation

The FTP sensor measures the difference between the pressure or vacuum in the fuel tank and outside air pressure. The control module provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the control module that can vary between 0.1-4.9 volts. As fuel tank pressure increases, FTP sensor voltage decreases, high pressure = low voltage. As fuel tank pressure decreases, FTP voltage increases, low pressure or vacuum = high voltage.