Sienna, Tacoma & 4Runner
- Wheel speed sensors on each wheel deliver an input signal to Anti-Lock Brake System (ABS) Electronic Control Unit (ECU). ABS 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 input signal to Engine Control Module (ECM).
- If problem exists with vehicle speed sensor, a Diagnostic Trouble Code (DTC) will be stored in Engine Control Module (ECM). For diagnosis of DTC, see appropriate TESTS W/CODES article.