PURGE VALVE LEAK DIAGNOSTIC SYSTEMS AND METHODS
First Claim
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1. A leak diagnostic system for a vehicle, comprising:
- a tank pressure module that selectively outputs first and second fuel tank pressures when an engine is shut down and when engine vacuum is greater than a predetermined engine vacuum, respectively; and
a leak diagnostic module that selectively diagnoses a leak in a fuel vapor purge valve based on said second fuel tank pressure when said first fuel tank pressure is less than a first predetermined pressure.
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Abstract
A leak diagnostic system for a vehicle comprises a tank pressure module and a leak diagnostic module. The tank pressure module selectively outputs first and second fuel tank pressures when an engine is shut down and when engine vacuum is greater than a predetermined engine vacuum, respectively. The leak diagnostic module selectively diagnoses a leak in a fuel vapor purge valve based on the second fuel tank pressure when the first fuel tank pressure is less than a first predetermined pressure.
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Citations
20 Claims
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1. A leak diagnostic system for a vehicle, comprising:
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a tank pressure module that selectively outputs first and second fuel tank pressures when an engine is shut down and when engine vacuum is greater than a predetermined engine vacuum, respectively; and a leak diagnostic module that selectively diagnoses a leak in a fuel vapor purge valve based on said second fuel tank pressure when said first fuel tank pressure is less than a first predetermined pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A leak diagnostic method for a vehicle, comprising:
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selectively outputting first and second fuel tank pressures when an engine is shut down and when engine vacuum is greater than a predetermined engine vacuum, respectively; and selectively diagnosing a leak in a fuel vapor purge valve of said vehicle based on said second fuel tank pressure when said first fuel tank pressure is less than a first predetermined pressure. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification