The main purpose of the purge control valve is to control the purging of fuel vapors precisely from the evaporative emission control system’s charcoal canister back into the engine. In modern cars, the mechanism is operated electrically.
The purpose of the EVAP system is to keep the tank's fuel vapors from escaping. These vapors are stored in a charcoal canister and then released back into the engine by the purge control valve. A faulty purge control valve may cause the “Check Engine" light to illuminate. Since the purge control valve is a small component, it is usually inexpensive to replace.