Evaporative Emissions System: Description and Operation

This system prevents raw fuel vapors from entering the atmosphere. Vapors which accumulate in the upper part of the tank, are routed to the charcoal canister when temperatures rise sufficiently to open the rollover valve. With engine off, these vapors are stored in the charcoal canister. During normal engine operation, the ECU deactivates the EGR/canister purge solenoid which allows intake manifold vacuum to draw vapors from the charcoal canister into the intake manifold, where they are burned. When the ECU activates the solenoid, vacuum is restricted, and purging of the vapor canister is limited.