4s-fe Ecu Pinout: [updated]

| Pin | Wire Color | Function | Signal Type | Notes | |------|------------|-----------|-------------|-------| | A1 | White/Red | +B (Main EFI Relay) | 12V Battery | Power input to ECU | | A2 | White/Red | +B1 (EFI Relay 2) | 12V Battery | Secondary power | | A3 | Yellow | Injector #1 (Cyl 1) | Ground switched | ECU grounds to fire | | A4 | Yellow/Black | Injector #3 (Cyl 3) | Ground switched | | | A5 | Black/Orange | IACV (ISCV) – Open coil | Duty cycle | Idle Air Control Valve | | A6 | Blue/Red | IACV (ISCV) – Closed coil | Duty cycle | | | A7 | Black/Brown | ELS (Electrical Load) | 12V (active high) | A/C or headlight signal | | A8 | Yellow/Green | Injector #2 (Cyl 2) | Ground switched | | | A9 | Yellow/Blue | Injector #4 (Cyl 4) | Ground switched | | | A10 | Black/White | E01 (Power Ground) | Ground | Heavy ground for injectors | | A11 | Brown/White | E02 (Power Ground) | Ground | Same as E01 | | A12 | Black/Yellow | Check Engine Light (W) | Ground to illuminate | Bulb on dash (12V via cluster) |

Here is why you need the correct pinout: 4s-fe ecu pinout

The car would start cold, idle for exactly seven minutes, then die like a guillotine blade dropped. No spark, no fuel, no warning. | Pin | Wire Color | Function |