Purpose

EVAP Control System Overview:

The Evaporative Emission ([1][2]EVAP) control system limits the fuel vapors from escaping into the atmosphere. The EVAP transfers the fuel vapor from the sealed fuel tank to an activated charcoal EVAP canister. The EVAP canister stores the vapors until the engine is able to use the extra fuel vapor.

When the engine is able to use the extra fuel vapor, the intake air flow purges the fuel vapor from the carbon element, and then the normal combustion process consumes the fuel vapor.

The system is required in order to detect the evaporative fuel system leaks as small as 0.040 between the fuel filler cap and the purge solenoid. The system can test the EVAP system integrity by applying a vacuum signal (ported or manifold) to the fuel tank in order to create a small vacuum.