Hyundai 31435-38100 Sensor-Fuel Tank Pressure

The Evaporative Emissions Control (EVAP) system is intended to capture fuel vapors and return them to the engine, to be burned in the the intake with the incoming air/fuel mixture. They consist of the FTFNC, EVAP, VPS, CCV, 2WV, and PV out of which all but the PV are found under the car. If temperature of gasoline in the fuel tank increases, this creates vapor that increases the pressure within the close container known as the vapor pressure sensor that feeds back to the PCM. The vapors pass through a two way valve and are then accumulated in the canister until the PCM triggers the purge control solenoid valve hence intake manifold vacuum will pull the vapors into the intake manifold. This system goes in a closed loop once the coolant temperature of the engine is high, thus, the PCM controls the vaporization to prevent a rich air-to-fuel in the mixture. In the process of purging, fresh air from the atmosphere is required for pressure equilibrium and the valve of the canister is opened and closed by referring to PCM. Thus, the diagnostic monitor of the EVAP system compares pressure to detect a leakage, and in case of leakage, the MIL turns on. The PCM also supervises the canister closed valve and pressure switching valve in order to perform effective check up, and the sequence is to be continued, while the engine is in closed loop. When it came to objectives such as the purge control solenoid valve, the procedure was removal of the battery and the engine cover, disconnecting of connectors and hoses among others, with installation being the reverse of the process of removal. The similar procedures of disconnecting and reinstalling apply on other components namely the two-way valve, EVAP canister, vapor pressure sensor, and canister closed valve.

The PCM monitors the pressure inside the EVAP system using the vapor pressure sensor. If a leak is detected, the Malfunction Indicator Light (MIL) or Check Engine light will turn on, and a Diagnostic Trouble Code (DTC) will be stored.