Circuit Description

VSS outputs a 4-pulse signal for every revolution of rotor shaft, which is driven by transmission output shaft. Signal is sent to instrument cluster to operate speedometer. Instrument cluster then sends signal to ECM. Signal is used by ECM to determine vehicle speed. DTC is set if there is no VSS signal to ECM while vehicle is being driven and park/neutral switch is off. Possible causes are:

• Defective vehicle speed sensor.
• VSS circuit is open or shorted.
• Defective instrument cluster.
• Defective ECM.