The EVAP purge solenoid controls the flow of vapors from the EVAP system to the intake
manifold. This normally closed solenoid is pulse width modulated (PWM) by the control module to
precisely control the flow of fuel vapor to the engine. The solenoid will also be opened during
some portions of the EVAP testing, allowing engine vacuum to enter the EVAP system.
Engine Emission Purge Valve Description