Canister Purge Control Valve: Description and Operation

When the vapor management valve is closed, the fuel tank is vented into the canister through the fuel tank roll-over valve. The canister absorbs the fuel vapor and prevents the release of hydrocarbons into the atmosphere. When the vapor management valve is opened, the canister is exposed to the intake manifold vacuum and the fuel vapor deposits are drawn into the manifold where they mix with the incoming air/fuel charge.
The evaporative emission fuel vapor management system is controlled by the powertrain control module according to calibrated data tables.