The purge control valve is part of the Evaporative Emission Control System (EVAP) of a vehicle. The EVAP system captures gasoline vapors coming from the fuel tank and routes them to be burned in the engine instead of venting into the atmosphere. Fuel vapors that are allowed to escape result not only in lost fuel but also emissions that are harmful to humans and the environment.
Also known as a purge solenoid, the purge control valve allows the fuel tank to be vented so that pressure does not build up inside, while at the same time preventing those vapors from escaping. Vapors that are collected are stored in a special vapor canister where they are absorbed by activated carbon (charcoal) and stored there until the engine control module (ECM) signals the purge valve (solenoid) to open. Once the purge control valve opens, the fumes stored in the canister are drawn out by the engine and burned as part of the combustion process.
When a purge control valve (solenoid) fails, it usually triggers the check engine light to come on. A diagnostic scan of the vehicle will reveal a trouble code related to pressure in the EVAP system. Besides the check engine light and related trouble code, other possible symptoms include:
To replace the purge control valve (solenoid), a technician will generally take the following steps: