| 摘要 |
A method of diagnosing components used for leak detection in a closed vapor handling system of an automotive vehicle, implemented by a system, the method including 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. The system includes a pressure switch, a control valve, a shut off valve, and a processor operatively coupled to the pressure sensing element, the control valve, and the shut off valve and receiving pressure signals from the pressure sensing element and sending signals to the control valve and the shut off valve, wherein the processor runs an engine, determines whether the pressure switch is closed, purges a canister, specifies a fail condition if the control valve is inoperative, ascertains whether the control valve is inoperative in a flow-through condition or inoperative in a non-flow-through condition, specifies a pass condition if the control valve is functioning, determines whether the shut off valve and the pressure switch are malfunctioning, and displays an error if at least one of the pressure switch, the shut off valve, and the control valve is malfunctioning.
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