The 2003 Lexus ES300 speed sensor detects the wheel speed and sends the appropriate signals to the ECU. The signal are used for control of both the ABS (antilock brake system) and system. The front rotor and rear rotor have 48 serrations. When the rotors rotate, the magnetic field emitted by the permanent magnet in the speed sensor generates an AC voltage.
Since the frequency of this AC voltage changes in proportion to the speed of the rotors (wheels), the frequency is used by the ECU to detect the speed of each wheel. The following schematic shows the 2003 Lexus ES300 Speed Sensor Wiring Diagram.