EVAP Check Valve

WARNING: This page is about a different variant/trim than selected.

The EVAP check valve is used on turbocharged engines to prevent boost pressure from forcing open the EVAP purge valve and entering the EVAP system. The valve is open under normal engine vacuum. The valve closes during boost conditions to prevent the fuel tank from being pressurized and hydrocarbons forced out of the EVAP system into the atmosphere through the EVAP canister vent valve. When the engine is OFF, or at atmospheric pressure, the EVAP check valve is in an indeterminate state. The EVAP check valve is an integral part of the EVAP purge valve assembly.

The EVAP dual check valve allows purge flow during boost conditions. Fuel vapors flow through the EVAP dual check valve to the intake air system upstream of the turbocharger before entering the intake manifold. When the engine is OFF, or at atmospheric pressure, the EVAP dual check valve is in an indeterminate state.