General Information

The evaporative emission system consists of an evaporative emission canister and an EVAP canister purge valve. A combination of plastic pipes and rubber hoses connect the canister to the fuel tank and the EVAP canister purge valve to the intake manifold.

In addition, the evaporative emission system uses a canister vent solenoid and a fuel tank pressure sensor which are used during the engine management system on board diagnostic routines. For further information regarding the diagnosis of this component and the system it is a part of, please refer to Computers and Control Systems; Testing and Inspection.

When the EVAP canister purge valve is closed, the fuel tank is vented into the EVAP canister through the fuel vapor vent valves. The EVAP canister absorbs the fuel vapor and prevents the release of hydrocarbons into the atmosphere. When the EVAP canister purge valve is opened, the EVAP 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 system is controlled by the powertrain control module according to calibrated data tables.