Canister Purge Solenoid: Description and Operation

PURPOSE
The canister purge solenoid allows manifold vacuum to purge the fuel vapors from the vapor canister when specific conditions are met.

OPERATION
Canister purge solenoid allows manifold vacuum to purge the canister when de-energized. The Electronic Control Module (ECM) supplies a ground to energize the solenoid (purge "OFF"). The purge solenoid, controlled by the ECM, is pulse width modulated (turned "ON" and "OFF" several times a second). The duty cycle (pulse width) is determined by the amount of air flow and the engine vacuum as determined by the Manifold Absolute Pressure (MAP) sensor input.