General Description

Enhanced Evaporative Control System:

PURPOSE
The Evaporative Emission (EVAP) control system limits fuel vapors from escaping into the atmosphere.

OPERATION
The EVAP system transfers fuel vapor from the sealed fuel tank to an activated carbon (charcoal) storage device (EVAP canister). The EVAP canister will store the vapors until the engine is able to use the extra fuel vapor.

Fuel Vapor Purge
When the engine is able to use the extra fuel vapor, the fuel vapor is purged from the carbon element by intake air flow and consumed in the normal combustion process.

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