Evaporative Emissions

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

In addition, the fuel vapor management 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 system, please refer to Computers and Control Systems; Testing and Inspection.

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.