Evaporative Emissions System: Description and Operation

Component Location:

The evaporative emission system:
^ is equipped with an On-board Refueling Vapor Recovery (ORVR) system.
^ prevents hydrocarbon emissions from reaching the atmosphere.
^ stores fuel vapors in the Evaporative Emission (EVAP) canister.
^ returns the stored fuel vapors to the engine during engine operation.
^ has an evaporative emission test port for testing purposes.

The fuel vapors are routed:
^ from the fuel tank through the fuel vapor control valve tube assembly.
^ from the fuel vapor control valve tube assembly through the EVAP canister purge outlet tube to the engine when the evaporative emission canister purge valve is opened by the Powertrain Control Module (PCM).

The fuel tank pressure sensor:
^ monitors the pressure inside the fuel tank.
^ provides a fuel tank pressure reading to the PCM during the OBDII test.
^ is located in-line above the fuel tank and is serviced as a fuel vapor control valve tube assembly.

The evaporative emission canister:
^ is located in the left rear quarter panel.
^ contains activated carbon.
^ stores fuel vapor.

The fuel tank filler cap:
^ relieves system pressure at 3.8 kPa (0.55 psi).

The canister vent solenoid:
^ seals the evaporative emission system for the OBDII leak check.
^ is mounted to the evaporative emission canister.
^ is repaired as a separate item.

The evaporative emission canister purge valve:
^ is located in the right front inner fender well.
^ regulates purging of the evaporative emission canister.
^ is controlled by the PCM.

The fuel vapor control valve tube assembly:
^ consists of the fuel vapor control valve, fuel vapor vent valve and an in-line fuel tank pressure sensor.
^ prevents suspended liquid fuel from being drawn into the evaporative emission canister along with the fuel vapors.
^ returns the liquid to the fuel tank.
^ includes a fresh air transfer tube routing fresh air between the canister vent solenoid hose and the fuel tank filler pipe assembly.
^ requires two grommets to seal the fuel vapor control valve and fuel vapor vent valve to the fuel tank.