4s-fe Ecu Pinout May 2026

Finding a verified 4S-FE ECU pinout can be tricky since these JDM engines (commonly found in the Toyota Corona, Carina, and Mark II) vary slightly by year and chassis (e.g., ST180 vs. ST190).

• Power: A1 (+12V constant) , C14 (+12V ignition), A7/A8 (Ground)
• Start signal: A15 (STA) – from starter solenoid
• Ignition: C1/C2 (NE+/-) , C3 (G1) … use entire distributor plug
• Injectors: A3 through A6 (ECU grounds injectors – remember to supply +12V separately)
• Fuel pump: You must bypass or wire the circuit opening relay (COR) using the STA signal and AFM flap switch (if equipped).

Power and Ground Pins

IGF (Ignition Feedback): A crucial "confirmation" signal sent back from the igniter to the ECU. If the ECU doesn't see IGF, it will cut fuel to prevent catalytic converter damage. 4s-fe ecu pinout

• Plug A (Left / 16-pin): Main power, grounds, injectors, ignition, O2 sensor.
• Plug B (Middle / 12-pin): Sensors (TPS, MAP/MAF, Water temp, IAT).
• Plug C (Right / 14-pin): Distributor (Ne, G signals), start signal, check engine light, diagnostic port.

In this guide, we will break down the Toyota 4S-FE ECU pinout, identifying the critical pins you need to know for diagnostics and wiring. Finding a verified 4S-FE ECU pinout can be