Toyota 4afe Ecu Pinout Info

If this sensor fails, the ECU may think the engine is permanently cold (-40°C), causing it to run extremely rich.

| Pin No. | Wire Color (Typical) | Signal Description | Connection / Notes | | :--- | :--- | :--- | :--- | | | Black/Red | BATT (Battery Power) | Constant +12V (Fuse Box) | | 2 | Black/Orange | M-REL (Main Relay) | Triggers Main EFI Relay Coil | | 3 | Black/White | +B (Main Power) | Switched +12V from EFI Main Relay | | 4 | – | Not Used | | | 5 | – | Not Used | | | 6 | Blue/Yellow | FC (Fuel Pump Control) | Opens Fuel Pump Circuit (Failsafe) | | 7 | Blue/Black | RSC (ISC Valve Close) | Idle Speed Control Valve | | 8 | Blue/Red | RSO (ISC Valve Open) | Idle Speed Control Valve | | 9 | Blue | #10 (Injector 1) | Fuel Injector #1 Driver | | 10 | Yellow | #20 (Injector 2) | Fuel Injector #2 Driver | | 11 | Blue/White | RCK (Tachometer) | Tachometer Output Signal | | 12 | – | Not Used | | | 13 | Yellow/Red | ELS (Electrical Load) | Headlights/Defogger Signal | | 14 | Blue/Black | W (Warning Light) | Check Engine Light (CEL) Output | | 15 | – | Not Used | | | 16 | – | Not Used | | toyota 4afe ecu pinout

: Injector pulse signals (usually paired, e.g., 1 & 3, 2 & 4). : Pressure Intake Manifold signal from the MAP sensor. : Coolant Temperature signal. : Intake Air Temperature signal. : 5V constant power supply to sensors like the TPS. If this sensor fails, the ECU may think

The following tables provide a breakdown of the common pin assignments for the 4AFE ECU: : Pressure Intake Manifold signal from the MAP sensor

: A 4-wire O2 sensor includes pins for the heater (+), heater ground (-), signal, and signal ground.

| Pin | Signal | Description | |------|--------|--------------| | E1 | E01 | Same as C3 – injector/igniter power ground | | E2 | E02 | Same as C4 – injector/igniter power ground | | E3 | E1 | Logic ground (same as C12) | | E4 | BATT | Constant 12V (ECU memory keep-alive) | | E5 | IGSW | Ignition switch 12V (ECU main power) | | E6 | VTA2 | TPS idle switch (closed throttle) | | E7 | VTA1 | TPS full range signal (duplicate of B1) | | E8 | VCC2 | 5V sensor supply (duplicate of B4) | | E9 | E2 | Sensor ground (duplicate of B3) | | E10 | VS | Vehicle speed sensor input (alternative) | | E11 | TACH | Tachometer output (to dash/cluster) | | E12 | IDL | Idle switch (closed throttle, alternative) |