Advanced Evaporative Emission System - From 99MY (NAS Only)

The Bosch Motronic 5.2.1 ECM includes control for the evaporative emissions system components, its purpose is to minimize the evaporative loss of fuel vapor from the fuel system to the atmosphere. This is achieved by venting the system through an EVAP canister filled with vapor absorbing charcoal. The charcoal acts like a sponge and stores the vapor until the canister is purged under the control of the ECM.

Fuel vapor is stored in the activated charcoal canister for retention when the vehicle is not operating. When the vehicle is operating, fuel vapor is drawn from the canister into the engine via a purge control valve. The vapor is then delivered to the intake plenum chamber to be supplied to the engine cylinders where it is burned in the combustion process.

See EMISSION CONTROL, Description and operation.