Wheel speed sensors on each wheel deliver an input signal to Anti-Lock Brake System (ABS) Electronic Control Unit (ECU). ABS ECU converts input signals from wheel speed sensors to a 4-pulse input signal to the instrument cluster. Instrument cluster then converts 4-pulse input signal to a rectangular waveform and then sends vehicle speed signal to ECM. On models with Vehicle Skid Control (VSC), ABS ECU may also be referred to as VSC ECU. On models without VSC, ABS ECU may also be referred to as ABS actuator and ECU. DTC is set if there is no vehicle speed signal to ECM while vehicle is being driven. Possible causes are:
Vehicle speed circuit is open or shorted between instrument cluster and ECM.