Fuel Tank Pressure Sensor

WARNING: This page is about a different car, the 2003 Pontiac Sunfire, 2003 Pontiac Grand Am, 2003 Oldsmobile Alero, and 2003 Chevrolet Cavalier. However, it is still accessible from the selected car via links, so may be relevant.

The Fuel Tank Pressure (FTP) sensor is a pressure transducer. The Powertrain Control Module (PCM) supplies about 5 volts on the FTP reference circuit. The PCM also supplies a signal and ground circuit to the FTP. When the fuel tanks are full, high pressure, a high voltage signal will be monitored by the PCM. The FTP sensor is threaded into the fuel tank HPL solenoid. The volume of CNG will vary with temperature and pressure. Accurate CNG fuel level cannot be determined by pressure only. To compensate for the different volume factors a Fuel Tank Temperature (FTT) sensor is mounted within the HPL. The PCM performs a calculation on the fuel tank pressure vs. the in-tank temperature. The PCM will then display the temperature corrected CNG fuel level. The CNG FTP sensor should not be confused with the gasoline FTP sensor that is utilized for Evaporate (EVAP) emissions monitoring.