Vehicle Speed Sensor
WARNING: This page is about a different car, the 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
Vehicle speed signal is delivered to ABS ECU by ABS wheel speed sensors. 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. Speed sensors are located at each wheel.