Before you start probing wires, it is essential to identify which ECU version you have. While the 4S-FE was used for several years, the most common ECU found in aftermarket swaps and popular models (like the ST202 Celica or T190 Corona) usually utilizes the Toyota 26+16+12 Pin configuration.
This setup consists of three plugs plugged into the ECU:
Note: Always check the sticker on your ECU (e.g., part numbers starting with 89661-) to confirm the diagram, as JDM variants can differ slightly from market to market.
| Pin | Wire Color | Signal | Description | |------|------------|--------|--------------| | B1 | B-R | +B | Battery power (EFI main relay) | | B2 | B-Y | +B1 | Battery power (injectors, sensors) | | B3 | B-O | E1 | Power ground (ECU) | | B4 | B-W | E2 | Signal ground (sensors) | | B5 | R | #10 | Injector 1 | | B6 | L | #20 | Injector 2 | | B7 | Y | #30 | Injector 3 | | B8 | L-B | #40 | Injector 4 | | B9 | W | IGT | Ignition timing signal to igniter | | B10 | R-L | IGF | Ignition confirmation from igniter | | B11 | G | G- | Distributor G signal (-) | | B12 | G-R | G+ | Distributor G signal (+) | | B13 | W | NE+ | Distributor NE signal (rpm) | | B14 | B | NE- | Distributor NE signal (-) | | B15 | B-O | STA | Starter signal (from ignition switch) | | B16 | G-W | NSW | Neutral start switch (auto) / clutch switch (manual) | | B17 | R-B | VTA | Throttle position sensor (TPS) signal | | B18 | B-Y | VC | TPS 5V reference | | B19 | G-B | IDL | Idle switch (closed throttle) | | B20 | L-R | PIM | Manifold absolute pressure (MAP) | | B21 | - | - | Not used | | B22 | G-R | FC | Fuel pump relay control |
| Pin | Wire Color | Function | Signal Type | Condition (Key ON, Engine OFF) | |-----|------------|----------|-------------|--------------------------------| | A1 | Black/Red | Battery Power (BATT) | 12V Constant | Always ~12V | | A2 | Black/Orange | Main Relay Power (+B) | 12V Switched | 12V when key ON | | A3 | White/Black | ECU Ground (E1) | Ground | <0.5V to chassis | | A4 | Brown | Sensor Ground (E2) | Ground | <0.1V (reference) | | A5 | Red/Blue | Throttle Position Sensor (VTA) | Analog 0-5V | ~0.5V (idle) to ~4.5V (WOT) | | A6 | Green/Black | Manifold Absolute Pressure (PIM) | Analog 0-5V | ~2.5-3.0V (sea level) | | A7 | Yellow/Green | Intake Air Temp (THA) | Resistance/Variable | ~2.0-3.0V at 20°C | | A8 | Blue/Yellow | Engine Coolant Temp (THW) | Resistance/Variable | ~2.0V cold, ~0.4V hot | | A9 | Pink | Oxygen Sensor (OX) | 0-1V Analog | N/A (engine running: 0.1-0.9V) | | A10 | White | Starter Signal (STA) | 12V Trigger | 12V while cranking | | A11 | Black/Yellow | Ignition Switch (IG SW) | 12V Input | 12V in ON/START | | A12 | Red/White | Neutral Start Switch (NSW) | Ground/12V | 0V in P/N (A/T) or clutch in (M/T) | | A13 | Blue/Red | Air Flow Meter (not used – MAP only) | N/A | N/C on 4S-FE (MAP based) | | A14 | Green/White | Knock Sensor (KNK) | AC signal | ~0V idle, ~0.5V under knock | | A15 | Light Green | Check Engine Light (W) | Output (Ground) | Sinks to ground when fault exists | | A16 | Yellow | Vehicle Speed Sensor (SPD) | Digital pulse | 0-5V pulses (4 pulses per rotation) |
The Toyota 4S-FE ECU pinout is your electrical roadmap. Whether reviving a barn-find Corona or swapping this bulletproof 1.8L into a project car, understanding the relationship between pin A15 (starter signal), pin C1 (NE pulse), and pin A7 (ground) will save you hours of frustration.
Final Pro Tip: Before condemning the ECU, verify every ground (A7, A8, C9) and every 5V reference. 90% of "ECU failure" cases on the 4S-FE are actually corroded harness connectors or a single dead sensor dragging down the entire 5V network.
Keep this guide bookmarked, invest in a $10 multimeter, and your 4S-FE will run for another 300,000 miles.
Do you have a specific 4S-FE pinout question for the Corona T170 vs. the Celica T200? Leave a comment below or consult the factory wiring diagram supplement for your chassis code.
The smell of burnt clutch and desperation hung heavy in the air of the garage.
Mark stared at the open hood of the '96 Camry. To the casual observer, it was a beige relic, a forgotten appliance of the automotive world. But to Mark, it was the "Millennium Falcon"—a car that shouldn’t be running, yet somehow defied the laws of entropy every single day. 4s-fe ecu pinout
Until today.
The engine bay was a chaotic mess. The previous owner, a man who evidently believed electrical tape was a valid substitute for proper connectors, had attempted a hack-job swap. The result was a harness that looked like a bowl of spilled spaghetti. The car cranked, but it wouldn't catch. The heart—the legendary 2.2L 5S-FE engine—was there, but the brain was disconnected.
"Come on, baby," Mark whispered, wiping grease from his forehead. "Talk to me."
He pulled up a stool and grabbed his laptop. The sun had set an hour ago, and the only light came from the flickering fluorescent tube overhead and the glow of the screen. He needed a map. He needed the Rosetta Stone for this specific engine.
He typed the sacred words into the search bar: 4s-fe ecu pinout.
The search results were a minefield of broken links, paywalls, and forum posts from 2003. But finally, deep in a forgotten thread on a JDM enthusiast forum, he found it. A grainy, scanned image of a wiring diagram. It was titled simply: Toyota 5S-FE / 4S-F ECU Pinout Identification.
Mark squinted at the screen. The diagram showed three rows of pins for the ECU connector: E9, E10, and E11. It looked like the cockpit of a spaceship.
"Okay," Mark muttered, tracing the lines with a greasy finger hovering over the keyboard. "Let's find out why you aren't firing."
He printed the grainy image and taped it to the fender of the car. His multimeter beeped as he turned it on. He was looking for the essentials: Power, Ground, and Signal.
He knelt by the passenger kick panel where the ECU lived, buried behind the carpet. He unplugged the harness connector. It was a mess of cut wires and splices. Before you start probing wires, it is essential
He looked at the pinout diagram. Pin 1 (E10): Injector. Pin 2 (E10): Injector. Pin 14 (E10): Igniter output.
"Ignition," Mark said. "Let's start there."
He probed the corresponding wire on the harness—a white wire with a black stripe. He turned the key to 'On'. The multimeter read 0.00 volts. Nothing.
"That's not good," he mumbled. He checked the
You're looking for the ECU pinout for a 4S-FE engine!
The 4S-FE engine is a 1.8L inline-4 cylinder engine produced by Toyota, used in various models such as the Toyota Camry, Corolla, and Solara.
Here is the ECU pinout for a 4S-FE engine:
Toyota 4S-FE ECU Pinout ( 1990-1996 models)
The ECU used in 4S-FE engines from 1990 to 1996 is the Toyota ECU type " 89661-..." or " 89761-...".
Here is a basic pinout of the ECU:
Connector 1 (J1, 26 pins)
| Pin # | Signal Name | Description | | --- | --- | --- | | 1 | EGT | Engine Ground | | 2 | IGT | Ignition Timing Signal | | 3 | IGF | Ignition Feedback Signal | | 4 | GND | Ground | | 5 | +B | Battery Voltage | | 6 | THA | Throttle Angle Sensor ( TPS) | | 7 | ODO | Odometer Signal | | 8 | ISC | Idle Speed Control | | 9 | SFT | Shift Solenoid (Automatic Transmission) | | 10 | L | Fuel Pump Relay | | 11 | W | Fuel Pump Monitor | | 12 | RCO | Resistance (Resistor) Check Output | | 13 | NE | Engine Speed Sensor (CKP) | | 14 | NTC | Coolant Temperature Sensor (ECTS) | | 15 | AFS | Air/Fuel Sensor (Oxygen Sensor) | | 16 | A/F | Air/Fuel Mixture Control | | 17 | Rx | Serial Communication Receive | | 18 | Tx | Serial Communication Transmit | | 19-26 | - | Not Used |
Connector 2 (J2, 28 pins)
| Pin # | Signal Name | Description | | --- | --- | --- | | 1 | +5V | 5V Reference Voltage | | 2 | GND | Ground | | 3 | VS | Vehicle Speed Sensor | | 4 | IAC | Idle Air Control Valve | | 5 | ISC2 | Idle Speed Control (auxiliary) | | 6 | F | Fuel Injector 1 ( Cylinder 1) | | 7 | F2 | Fuel Injector 2 (Cylinder 2) | | 8 | F3 | Fuel Injector 3 (Cylinder 3) | | 9 | F4 | Fuel Injector 4 (Cylinder 4) | | 10 | IG | Ignition Coil | | 11 | - | Not Used | | 12-28 | - | Not Used |
Additional notes:
Keep in mind that ECU pinouts can vary across different models and years, and this information might not be applicable to all 4S-FE engines.
Would you like to know more about a specific aspect of the ECU or engine?
Two main connectors:
Wire colors: Toyota standard (e.g., B-R = Black/Red, L-Y = Blue/Yellow)
Symptoms: Random misfires, erratic idle, transmission shifting hard (AT), no start. Fix: Open the ECU. Look for electrolytic capacitors (cylindrical components) near the harness plug. If they are leaking brown/black goo onto the circuit board, you need immediate repair. Action: Desolder and replace all capacitors (typically 100µF, 220µF, 470µF values). Clean the board with isopropyl alcohol. Note: Always check the sticker on your ECU (e
