Fuel Tank Pressure (FTP) Sensor

The fuel tank pressure (FTP) sensor, measures the difference between the fuel tank and outside air pressure. The FTP sensor is an integral part of the EVAP vacuum leak pump assembly. The PCM provides a 5-volt reference and a ground to the FTP sensor. The FTP sensor provides a signal voltage back to the PCM that can vary between 0.1 and 4.9 volts. As the fuel tank pressure increases, the FTP sensor voltage decreases, as the fuel tank pressure decreases the FTP sensor voltage increases. High pressure = high voltage. Low pressure vacuum = low voltage.