Feedback signal for closed-loop fuel management.
On OBD-I 4A-FE systems, locate the "Diagnostic" box under the hood. Use a paperclip to jumper pins TE1 and E1 . Turn the ignition key to ON. Count the flashes of the Check Engine Light on the dashboard to read manual fault codes. toyota 4afe ecu pinout
The wires for the NE (crank signal), G1/G2 (cam signals), and KNK (knock sensor) use shielded jackets to prevent electrical noise from corrupting the signals. When splicing these lines during a swap, make sure to preserve or recreate the grounding shield mesh. Feedback signal for closed-loop fuel management
| Code | Fault | Related Pins | |------|-------|----------------| | 11 | No IGF signal | Pin 13 (IGF) | | 12 | No G signal (distributor) | Pin 11 (G-) | | 13 | No NE signal (cam/crank) | Pin 11 circuit | | 14 | No IGt signal | Pin 12 (IGt) | | 21 | Oxygen sensor fault | Pin B4 (O2), B5 (HT) | | 22 | Coolant temp sensor | Pin 10 (THW) | | 24 | Intake air temp | Pin B7 (ACT) | | 31 | Airflow meter/MAP | Pin 9 (PIM) | | 41 | TPS circuit | Pin 7 (VTA), Pin 8 (VC) | | 51 | Switch condition (A/C, NSS) | Pin A14, B2, B10 | Turn the ignition key to ON
| 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 | |
Main computer grounds connected to the engine block or chassis.
Note: Wire colors can change depending on whether the vehicle was built in Japan, the US, or Europe. Always verify pins by location and voltage behavior rather than color alone. Power and Ground Pins Pin Acronym Pin Function Description Typical Voltage Switched Power 12V supply from the EFI Main Relay when ignition is ON +B1 Switched Power Backup Secondary 12V supply line for system redundancy BATT Constant Battery Direct memory power from EFI fuse; retains diagnostic codes Constant 12V E1 Engine Ground Primary housing/chassis ground for the ECU E2 Sensor Ground Clean, isolated ground return loop specifically for sensors E01 / E02 Power Grounds