Vehicle speed sensor diagnostic system and method
AssigneeGM Global Technology Operations LLC
InventorTodd J. Thor
Life of this patent
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Abstract
A diagnostic system for a vehicle speed sensor is provided. The system includes: an upshift module that selectively initiates an upshift of a transmission based on a vehicle speed sensor (VSS) signal; a speed drop detection module that monitors at least one of engine speed and input speed for a reduction in speed due to said upshift; and a torque request module that monitors engine torque and selectively diagnoses a VSS malfunction based on said speed reduction and said engine torque.
Claims11
A diagnostic system for a vehicle speed sensor, the diagnostic system comprising:
- an upshift module that i) receives a vehicle speed sensor (VSS) signal indicative of a vehicle speed and ii) initiates an upshift of a transmission in response to the vehicle speed being less than a predetermined vehicle speed threshold and an engine speed being greater than a predetermined engine speed threshold;
- a speed drop detection module that determines when the engine speed decreases in response to the upshift;
- and
- a torque request module that diagnoses a VSS malfunction if:
- a determination is made that the engine speed decreased in response to the upshift;
- and
- a determination is made after the upshift that engine torque did not decrease and a determination is made after the upshift that throttle position did not decrease.
A method of diagnosing a malfunction of a speed sensor, comprising:
- receiving a vehicle speed sensor (VSS) signal indicative of a vehicle speed;
- initiating an upshift of a transmission in response to the vehicle speed being less than a predetermined vehicle speed threshold and an engine speed being greater than a predetermined engine speed threshold;
- determining when the engine speed decreases in response to the upshift;
- and
- diagnosing a VSS malfunction if:
- a determination is made that the engine speed decreased in response to the upshift;
- and
- a determination is made after the upshift that engine torque did not decrease and a determination is made after the upshift that throttle position did not decrease.
Dependencies are inferred from the claim text.