This guide provides a comprehensive breakdown of the Toyota 3S-FE engine control unit (ECU) pinout to assist with diagnostics, engine swaps, and performance tuning. Understanding the 3S-FE Control Logic

Because of these variations, searching for a single "3S-FE ECU pinout" can be frustrating. One PDF might show a 22-pin connector, while your ECU has three large 26-pin connectors.

: Common on Celica and MR2 models, sometimes compatible with certain 3S-FE variations.