Vehicle Speed Sensor: 4Runner
WARNING: This page does not describe the selected car, but rather 10 other vehicles, including the 2002 Toyota Tundra, 2002 Toyota Tacoma, 2002 Toyota Sienna, 2002 Toyota Sequoia, and 2002 Toyota Land Cruiser. However, it is still accessible from the selected car via links, so may be relevant.
Wheel speed sensors on each wheel deliver an input signal to Vehicle Skid Control (VSC) Electronic Control Unit (ECU). VSC 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 Engine Control Module (ECM). If problem exists with vehicle speed signal, a Diagnostic Trouble Code (DTC) may be stored in Engine Control Module (ECM). See TESTING PROCEDURE under SELF-DIAGNOSTIC SYSTEM in appropriate SELF-DIAGNOSTICS article for retrieving of DTCs.