Patent ID: 6626032
Filing Date: 2003-09-30
Classification: F02M

Abstract:
A method of diagnosing components used for leak detection in a closed vapor handling system of an automotive vehicle comprising:providing leak detection components including a pressure switch that moves at a given relative vacuum, a control valve that operates to allow and prevent flow therethrough, and a shut off valve that operates to allow and prevent flow therethrough; running an engine; determining whether the pressure switch is closed; purging a canister; specifying a fail condition if the control valve is inoperative after purging; ascertaining whether the control valve is inoperative in a flow-through condition or inoperative in a non-flow-through condition if a fail condition is specified; specifying a pass condition if the control valve is functioning after purging; determining whether the shut off valve and pressure switch are malfunctioning if a pass condition is specified based on whether the pressure switch is open; and displaying an error if a component is malfunctioning.