Circuit Description

Anti-Lock Brake System (ABS) wheel speed sensor detects wheel speed and sends signals to ABS ECU. The ABS ECU converts signals into a 4-pulse signal and outputs signal to instrument cluster. Instrument cluster converts signal to a more precise waveform and outputs signal to ECM. ECM determines vehicle speed based on frequency of these pulse signals. DTC is set if there is no VSS signal to ECM while vehicle is being driven and park/neutral position switch is off. Possible causes are:

• Defective vehicle speed sensor.
• Vehicle speed sensor circuit is open or shorted.
• Defective instrument cluster.
• Defective ABS ECU.
• Defective ECM.