Evaporative Emissions System: Description and Operation

Fig. 2 EVAP Canister:

PURPOSE
The evaporation control system prevents the emission of fuel tank vapors into the atmosphere.

OPERATION
When fuel evaporates in the fuel tank, the vapors pass through vent hoses or tubes to a charcoal canister. The canister temporarily holds the vapors.

Through the duty cycle EVAP purge solenoid, the PCM allows intake manifold vacuum to draw vapors from the charcoal canister into the combustion chambers during certain operating conditions.
- The solenoid regulates vapor flow from the canister to the engine.

The evaporative system uses specially manufactured hoses. If they need replacement, only use original equipment fuel vapor resistant hose.