Circuit Description

The Evaporative (EVAP) emission canister purge valve is used to purge fuel vapor from the EVAP canister to the intake manifold. The EVAP canister purge valve is Pulse Width Modulated (PWM). Ignition voltage is supplied directly to the EVAP canister purge valve. The Engine Control Module (ECM) controls the solenoid by grounding the control circuit with a solid state device called a driver. The driver is equipped with a feedback circuit that is pulled-up to a voltage. The ECM can determine if the control circuit is open, shorted to ground, or shorted to a voltage by monitoring the feedback voltage.