Method for diagnosing a failure of an output shaft speed sensor of an automatic transmission for a vehicle
First Claim
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1. A method for diagnosing a failure of an output shaft speed sensor of an automatic transmission, comprising:
- determining whether the transmission is in a forward gear;
determining whether a failure criterion exists based on at least one of a current gear, an input shaft speed, an output shaft speed, or an engine speed, if the transmission is in a forward gear; and
maintaining the current gear if a downshift criterion exists, or upshifting a gear if an upshift criterion exists, if the failure criterion exists.
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Abstract
A method and apparatus for diagnosing a failure of an output shaft speed sensor of an automatic transmission is provided, which comprises: determining whether a current transmission is a forward driving range; determining whether a failure criterion exists based on a current gear, an input shaft speed, an output shaft speed, and an engine speed, if the current transmission is the forward driving range; and maintaining the current gear if a downshift criterion exists, or upshifting a gear if a upshift criterion exists, if the failure criterion exists.
9 Citations
31 Claims
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1. A method for diagnosing a failure of an output shaft speed sensor of an automatic transmission, comprising:
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determining whether the transmission is in a forward gear;
determining whether a failure criterion exists based on at least one of a current gear, an input shaft speed, an output shaft speed, or an engine speed, if the transmission is in a forward gear; and
maintaining the current gear if a downshift criterion exists, or upshifting a gear if an upshift criterion exists, if the failure criterion exists. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14)
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15. A system for diagnosing a failure of an output shaft speed sensor of an automatic transmission, comprising:
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an inhibitor switch for detecting what gear the transmission is in;
an input shaft speed sensor detecting a turbine shaft speed and generating a corresponding signal;
an output shaft speed sensor detecting an output shaft speed and generating a corresponding signal;
an engine speed sensor detecting an engine speed and generating a corresponding signal; and
a control unit programmed to execute instructions comprising;
determining whether the transmission is in a forward gear;
determining whether a failure criterion exists based on a current gear, an input shaft speed, an output shaft speed, and an engine speed, if the transmission is in a forward gear; and
maintaining the current gear if a downshift criterion exists, or upshifting a gear if a upshift criterion exists, if the failure criterion exists. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. A method for diagnosing a failure of an output shaft speed sensor of an automatic transmission, comprising:
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determining whether the transmission is in a forward gear;
determining whether a failure criterion exists based on the forward gear, an input shaft speed, and an output shaft speed; and
determining that the output shaft speed sensor has failed based on the failure criterion existing. - View Dependent Claims (30, 31)
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Specification