Method for diagnosing a failure of an output shaft speed sensor of an automatic transmission for a vehicle

摘要

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.