Evaporative Emissions: Notes

The Evaporative Emission (EVAP) system consists of the:

• EVAP  canister.
• EVAP  canister purge valve.
• fuel tank.
• fuel vapor tubes
• natural vacuum leak detection module.

The EVAP  system:

• prevents hydrocarbon emissions from reaching the atmosphere.
• stores fuel vapors in the EVAP  canister that are generated during vehicle operation hot soak or vehicle refueling, until they can be consumed by the engine during normal engine operation.
• routes the stored fuel vapors to the engine during engine operation.

The fuel vapors are routed:

• to the EVAP  canister through a vapor tube.
• to the engine when the EVAP  canister purge valve is opened.

The EVAP  canister:

• is located under the rear of the vehicle.
• contains activated carbon.
• stores fuel vapors.

The EVAP  canister purge valve:

• is normally closed.
• regulates the purging of the EVAP  canister.

The natural vacuum leak detection module:

• completes a series of checks to confirm the integrity of the enhanced EVAP  system components in the engine running state and the ignition OFF state.

Refer to the INTRODUCTION - GASOLINE MODELS for additional information on the EVAP  system.