Vehicle Emission Vacuum Routing

Evaporative Emissions

The Evaporative Emission (EVAP) system consists of the following components:

- EVAP (Evaporative Emission) canister (located in front of the fuel tank)

- EVAP (Evaporative Emission) canister purge valve (located on the intake manifold)

- Dual check valve (3.5L Gasoline Turbocharged Direct Injection (GTDI) engine) (part of the canister purge valve)

- Vapor ejector (3.5L GTDI (Gasoline Turbocharged Direct Injection) engine) (located in front of the engine)

- EVAP (Evaporative Emission) canister vent solenoid and dust separator assembly (located on the front of the EVAP (Evaporative Emission) canister)

- Fuel Tank Pressure (FTP) sensor and vapor tube assembly (located on top of the fuel tank)

- Vapor tubes

- Fresh air hose (located on top of the transmission)

The EVAP (Evaporative Emission) system:

- prevents hydrocarbon emissions from reaching the atmosphere.

- stores fuel vapors in the EVAP (Evaporative Emission) canister that are generated during vehicle operation or hot soak, until they can be consumed by the engine during normal engine operation.

- routes the stored fuel vapors to the engine during engine operation.

- is controlled by the PCM which, using various sensor inputs, calculates the desired amount of purge flow. The PCM regulates the purge flow, induced by the application of intake manifold vacuum, by varying the duty cycle applied to the EVAP (Evaporative Emission) canister purge valve.

The fuel vapors are routed:

- from the fuel tank through the fill limit valve and fuel vapor vent valve. The fuel vapor vent valves are part of the fuel tank assembly and cannot be serviced separately.

- to the EVAP (Evaporative Emission) canisters through a vapor line.

- to the engine when the EVAP (Evaporative Emission) canister purge valve is opened by the PCM.

The EVAP (Evaporative Emission) canister:

- contains activated carbon.

- stores fuel vapors.

The EVAP (Evaporative Emission) canister purge valve:

- is normally closed.

- regulates the purging of the EVAP (Evaporative Emission) canister.

- is controlled by the PCM.

The dual check valve (3.5L GTDI (Gasoline Turbocharged Direct Injection) engine):

- routes fuel vapors to the intake manifold when the intake manifold is not pressurized.

- routes fuel vapors to the vapor ejector when the intake manifold is pressurized.

The vapor ejector (3.5L GTDI (Gasoline Turbocharged Direct Injection) engine):

- is a venturi valve.

- uses pressurized air from the RH turbocharger-to-Charge Air Cooler (CAC) tube to route fuel vapors to the Air Cleaner (ACL) outlet tube-to-LH turbocharger tube.

The EVAP (Evaporative Emission) canister vent solenoid:

- is controlled by the PCM.

- is normally open.

- seals the EVAP (Evaporative Emission) system for the inspection and maintenance (I/M 240) test and OBD (On-Board Diagnostic) II leak and pressure tests.

The EVAP (Evaporative Emission) dust separator:

- prevents suspended dust and dirt particles from entering the EVAP (Evaporative Emission) system.

- is serviced as a separate item.

The FTP (Fuel Tank Pressure) sensor:

- measures the pressure levels in the fuel tank continuously.

- serves as an input to the PCM.

Vehicle Emission Vacuum Routing

3.5L Gasoline Turbocharged Direct Injection (GTDI)










3.7L










5.0L










6.2L