Fuel Tank Pressure Sensor Quick-Fix. The 3 wire fuel tank pressure sensor, is connected to the fuel tank by a hose, and to the ECM. The ECM uses this value to run the EVAP monitor. This sensor has no bearing on how the engine runs. Here are the facts about the fuel tank pressure sensor: 1) The fuel tank pressure sensor is a 0 to 5 volt sensor. 2) You should NOT see a stuck on 0 or 5 volt signal value, using a scanner or volt meter. It has to be somewhere in between.