EVAP Purge Valve (8/18) [2017-2022, B4204T27 | 2018-2022, B4204T28 | 2021-2022, B420T]: Description

The Evaporative Emission System (EVAP) purge valve is used to open and close the connection between the charcoal canister and the intake manifold. The EVAP purge valve controls the flow of fuel vapors to be re-introduced into the engine. The Engine Control Module (ECM) controls the flow rate by regulating the duty cycle of a pulse width modulated PWM signal sent to the EVAP purge valve.