Evaporative Emission Control System: Description

Evaporative Emission Control System prevents fuel vapor stored in fuel tank from draining into the atmosphere.

When the fuel evaporates in the fuel tank, the vapor passes through vent hoses or tubes to EVAP. canister filled with charcoal and the EVAP. canister temporarily holds it with charcoal. If ECM wants to draw the gathered vapor into the combustion chambers during certain operating conditions, it will make vacuum in intake manifold to move it.