EVAP System Components

WARNING: This page is about a different car, the 2017 Chevrolet Spark. However, it is still accessible from the selected car via links, so may be relevant.

The EVAP system is made up of the following components:

EVAP Canister

The EVAP canister is a sealed unit with 3 ports. It is filled with carbon pellets used to absorb and store fuel vapors. Fuel vapor is stored in the canister until the ECM determines that the vapor can be consumed in the normal combustion process.

EVAP Purge Solenoid Valve

The EVAP purge solenoid valve controls the flow of vapors from the EVAP system to the intake manifold. This normally closed valve is pulse width modulated (PWM) by the ECM to precisely control the flow of fuel vapor to the engine.

EVAP Air Inlet

The EVAP air inlet filters air entering the EVAP canister.

Purge Tube Check Valve

Turbocharged vehicles have a check valve in the purge tube, between the EVAP purge solenoid valve and the intake manifold to prevent pressurization of the EVAP system under boost conditions. There is one application, the 2.0L LHU that has this check valve between the EVAP purge solenoid valve and the EVAP canister.

Fuel Fill Cap

The fuel fill cap is equipped with a seal and a vacuum relief valve and is tethered. A torque-limiting device prevents the cap from being over tightened. To install the cap, turn the cap clockwise until you hear clicks. This indicates that the cap is correctly torqued and fully seated. A built-in device indicates that the fuel filler cap is fully seated.

Capless Fuel Fill

Some vehicles may have a capless fuel fill design behind a locking fuel door. There is no fuel fill cap to remove. One just fully inserts the fuel nozzle into the fill neck, making sure it latches before refueling. Flapper valves close to seal this interface once the fill nozzle is removed.