# US 8,543,284 B2 · Vehicle speed sensor diagnostic system and method > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,543,284 B2 - Document ID: US8543284B2 - Status: Granted - Kind: B2 - Application number: 11/468,021 - Filed: 2006-08-29 - Published: 2008-03-06 - Granted: 2013-09-24 - Earliest claimed: 2006-08-29 - Assignees: GM Global Technology Operations LLC - Applicants: Todd J. Thor - Inventors: Todd J. Thor - Web page: https://patentgrep.com/patent/US8543284B2 ## CPC - F16H 61/12: Detecting malfunction or potential malfunction, e.g. fail safe (in control of hydrostatic gearing F16H61/4192) {; Circumventing or fixing failures} - G05B 9/02: electric - B60W 2050/0215: {Sensor drifts or sensor failures} - B60W 2510/0657: Engine torque - B60W 2520/10: Longitudinal speed - F16H 59/14: Inputs being a function of torque or torque demand - F16H 59/36: Inputs being a function of speed - F16H 59/44: dependent on machine speed {, e.g. the vehicle speed} (F16H59/46 takes precedence) - F16H 2059/147: {Transmission input torque, e.g. measured or estimated engine torque} - F16H 2059/366: {Engine or motor speed} - F16H 2061/1208: {with diagnostic check cycles; Monitoring of failures} - F16H 2061/1284: {the failing part is a sensor} - F16H: GEARING - G05B: CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS (systems for controlling or regulating non-electric variables G05D; systems for regulating electric or magnetic variables G05F; control devices or systems insofar as characterised by mechanical features only G05G) - B60W: CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT ## 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. ## Claims ### Claim 1 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. ### Claim 2 (depends on 1) The diagnostic system of claim 1 wherein the upshift module initiates the upshift further in response to a determination that the transmission is operating in a drive range. ### Claim 3 (depends on 1) The diagnostic system of claim 1 wherein the speed drop detection module determines that the engine speed decreases based on a difference between a first engine speed determined before initiating the upshift and a second engine speed determined after initiating the upshift. ### Claim 4 (depends on 1) The diagnostic system of claim 1 wherein the engine torque is determined based on engine operating parameters. ### Claim 5 (depends on 1) The diagnostic system of claim 1 wherein said torque request module diagnoses the VSS malfunction in response to a change in the throttle position being within a predetermined negative range and the engine speed being decreased. ### Claim 6 (depends on 1) The diagnostic system of claim 1 wherein the torque request module sets a diagnostic code based on the VSS malfunction. ### Claim 7 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. ### Claim 8 (depends on 7) The method of claim 7 wherein the initiating the upshift occurs in response to a determination that the transmission is operating in a drive range. ### Claim 9 (depends on 7) The method of claim 7 wherein the determining that the engine speed decreases further comprises determining a difference between a first engine speed determined before initiating the upshift and a second engine speed determined after initiating the upshift. ### Claim 10 (depends on 7) The method of claim 7 wherein the diagnosing the VSS malfunction further comprises diagnosing the VSS malfunction in response to a change in the throttle position being within a predetermined negative range and the engine speed being decreased. ### Claim 11 (depends on 7) The method of claim 7 further comprising setting a diagnostic code based on the VSS malfunction.