Note the exact year, model, transmission, and country of origin for the vehicle that the ECU belonged to.
Starter motor signal (tells ECU the engine is actively cranking). Step-by-Step Guide to Identifying Unknown 89661 Pinouts
Do not bundle sensor grounds ( E2 ) together with power grounds ( E01 ). Doing so introduces electrical noise into your sensor readings, causing erratic idling and tuning issues. toyota 89661 ecu pinout
When looking at a factory Toyota service manual for an 89661 ECU, you will encounter standard abbreviations. Use this reference table to decode your specific board layout: Abbreviation Function Description Injector Fire Signals Triggers the grounding circuit to open fuel injectors. IGT (1, 2, 3...) Ignition Timing Output signal from ECU to igniter to trigger spark. IGF Ignition Feedback Confirmation signal sent back from the igniter to the ECU. NE+ / NE- Crankshaft Position Engine speed signal from the crank sensor. G1 / G2 / G+ Camshaft Position Identifies cylinder position for sequential injection. VCC 5V Sensor Power Clean 5V power supply output from ECU to sensors. VTA Throttle Position Analog voltage input from the Throttle Position Sensor. PIM / VG MAP / MAF Sensor Manifold Pressure (PIM) or Mass Airflow (VG) input. THW Water Temperature Input from the Engine Coolant Temperature (ECT) sensor. THA Intake Air Temp Input from the Intake Air Temperature (IAT) sensor. OX1 / HT1 Oxygen Sensor O2 sensor signal input (OX) and heater control (HT). FC Fuel Control Triggers the circuit opening relay to run the fuel pump. SPD Speed Signal
Oxygen sensor signal input and heater control lines. 4. Representative Wire Diagram Framework Note the exact year, model, transmission, and country
Engine load sensors. PIM indicates a Manifold Absolute Pressure (MAP) sensor; VG indicates a Mass Air Flow (MAF) sensor. THW: Engine Coolant Temperature (ECT) sensor input. THA: Intake Air Temperature (IAT) sensor input.
If you tell me the exact ECU part number (full 89661‑xxxxx), vehicle year, model, and engine code, I will produce a specific pin‑for‑pin mapping and a tailored bench test harness diagram for that unit. Doing so introduces electrical noise into your sensor
Switched 12V power coming from the EFI Main Relay.
Large, weather-sealed levers that lock the wiring harness directly into an ECU mounted under the hood. Essential Pin Acronyms and Meanings