Toyota 4afe Ecu Pinout Upd Jun 2026
For more detailed information on the Toyota 4AFE ECU pinout, consult the following resources:
The ECU calculates ignition timing and sends a 5V pulse via to the igniter. The igniter collapses the coil ground, sparking the plug.
Camshaft position positive signal.
The pinout below covers the most common found in the 1992–1995 Corolla/Geo Prizm (AE101 chassis). toyota 4afe ecu pinout
| Pin | Wire Color | Function | Signal Type | | :--- | :--- | :--- | :--- | | A1 | Black/Red (B-R) | Battery Power (Constant +12V) | Power | | A2 | Black/Yellow (B-Y) | Main Relay (EFI Relay) Control | Output | | A3 | Black/Orange (B-O) | Injector #4 | Output (Ground switched) | | A4 | Black/White (B-W) | Injector #2 | Output (Ground switched) | | A5 | – | Not used | – | | A6 | Red/Blue (R-B) | ISC Valve (Idle Speed Control) – S1 | Output | | A7 | Yellow/Blue (Y-B) | ISC Valve – S2 | Output | | A8 | Blue (L) | ISC Valve – S3 | Output | | A9 | Yellow/Black (Y-B) | ISC Valve – S4 | Output | | A10 | White/Black (W-B) | ECU Ground (Power ground) | Ground | | A11 | Brown/Black (BR-B) | ECU Ground (Power ground) | Ground | | A12 | – | Not used | – | | A13 | Light Green (LG) | Injector #3 | Output (Ground switched) | | A14 | Light Green/Red (LG-R) | Injector #1 | Output (Ground switched) | | A15 | Red (R) | Check Engine Light (MIL) | Output (Ground switched) | | A16 | Yellow (Y) | Fuel Pump Control (to Circuit Opening Relay) | Output |
Igniter sends this back to confirm a spark occurred. NE Engine Speed (RPM) Signal Generated by the pickup coil inside the distributor G1 / G2 Camshaft Position Signals Helps the ECU determine TDC for Cylinder #1 Fuel and Air Sensors
8-bit processor, typically utilizing two or three yellow/grey plugs (usually 10-pin, 18-pin, or 14-pin configurations). For more detailed information on the Toyota 4AFE
To help narrow down your specific wiring project, could you let me know the of the donor car, whether it uses a distributor or coil packs , and if you are doing a custom engine swap or troubleshooting an existing issue? Share public link
| 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 | |
Understanding the is essential for DIY mechanics and enthusiasts working on the iconic 1.6L engine found in many Corolla and Celica models . Whether you are troubleshooting a no-start issue, performing an engine swap, or installing an aftermarket piggyback system, having an accurate wiring map is your first step. Toyota 4A-FE ECU Pinout Overview The pinout below covers the most common found
Toyota used similar-looking connectors across the 4A-FE, 7A-FE, and 4A-GE engines, but the indexing tabs differ. Never force a plug into the ECU socket.
You should see a pulsing voltage signal alternating between 0V and 5V.
One of the most practical uses of the ECU pinout is retrieving diagnostic trouble codes. For OBD-I Toyota ECUs, including many 4A-FEs, you don't need a scanner. Follow this simple procedure:
Below is the standard pinout for a 22-pin (B), 16-pin (A), and 16-pin (C) connector layout. View from the (back of the connector) with the locking tab facing up or down as noted.