Canister Purge Solenoid: Description and Operation

When energized, the evaporative canister purge valve allows fuel vapor to flow from the EVAP canister to the engine. When the purge valve is commanded open, fresh air is drawn into the canister through the vent valve, and the vapors that were in the canister are consumed in the normal combustion process. The normally closed valve is pulse width modulated by the ECM in order to precisely control the vapor flow. The valve also opens during the Enhanced Evaporative Diagnostic Test in order to create a vacuum in the fuel tank and then closed in order to seal the system.