Two unrelated failures. The fuel tank vent valve is part of the EVAP (emissions) system. It opens/closes to remove excess fuel vapor from the vent canister and test the EVAP system.
The fuel rail pressure sensor on the other hand is part of the system that controls the fuel pressure the engine runs at. It sends a signal to the ECM which then uses that along with other sensor data to control the fuel pump driver module which varies the fuel pump speeds in order to regulate fuel delivery based on what the ECM thinks the engine needs.
Wednesday, May 31st, 2017 AT 3:21 PM