Circuit Description

Skid control Electronic Control Unit (ECU) receives vehicle speed input from ABS speed sensors (wheel speed sensors). Skid control ECU converts these signal into a 4-pulse signal and outputs them 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. Possible causes are:

• Defective Vehicle Speed Sensor (VSS).
• VSS circuit is open or shorted.
• Defective instrument cluster.
• Defective skid control ECU.
• Defective ECM.