Description And Operation: Description

Evaporative Emission Control System prevents fuel vapor stored in fuel tank from vaporizing into the atmosphere. When the fuel evaporates from the fuel tank, the vapor passes through vent hoses or tubes into canister filled with charcoal and the canister temporarily holds the vapor in the charcoal.

If ECM determines to draw the gathered vapor into the combustion chambers at certain operating conditions, it will use vacuum in the intake manifold to move it.