Evaporative Emissions System: Operation

When engine is not running, fuel vapors from fuel tank flow to carbon canister for storage. The check and cut valve (if equipped) prevents pressure or vacuum from forming in system. On GLC Station Wagon and B2000 models, when engine is started, manifold vacuum opens evaporative shutter valve to allow fresh air into carburetor. On all models, when engine coolant temperature reaches approximately 131 °F (55°C), water thermo valve opens and intake manifold vacuum is directed to purge control valve. When manifold vacuum opens purge control valve, fresh air is drawn through inlet hole at bottom of canister. Vapors are drawn into the engine and burned.