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Diagnosis of components used for leak detection in a vapor handling system

  • US 6,626,032 B2
  • Filed: 02/21/2001
  • Issued: 09/30/2003
  • Est. Priority Date: 02/22/2000
  • Status: Expired due to Fees
First Claim
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1. 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.

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