Vehicle Speed Sensor

Wheel speed sensors on each wheel deliver an input signal to the Anti-Lock Brake System (ABS) Electronic Control Unit (ECU). The ABS ECU converts input signals from wheel speed sensors to a 4-pulse input signal to the instrument cluster. The instrument cluster then converts the 4-pulse input signal to a rectangular waveform and then sends the input signal to the Engine Control Module (ECM). The ECM determines the vehicle speed by using the input signal. The ECM uses input signal for controlling fuel injection system, ignition timing (spark advance), idle speed control system (some models) and electronic control of automatic transmission/transaxle (some models).