Circuit Description
WARNING: This page is about a different car, the 2003 Toyota 4Runner. However, it is still accessible from the selected car via links, so may be relevant.
The speed sensor for skid control ECU detects the wheel speed and sends the appropriate signals to the skid control ECU. The skid control ECU converts these signals into a 4-pulse signal and outputs it to the combination meter. After this signal is converted into a more precise rectangular waveform by the waveform shaping circuit inside the combination meter (instrument cluster), it is then transmitted to the ECM. The ECM determines the vehicle speed based on the frequency of these pulse signals.