: The sticker on the ECU case will have the full number (e.g., 89661-XXXXX).
Ignition Trigger. Output signal from the ECU to command the igniter/coil to fire.
4A-GE, 3S-GTE (Gen 2/3), 1UZ-FE (Early), 7M-GTE.
A well-known issue with the 89661 series (especially the -50102 from the toyota 89661 ecu pinout
High risk of frying the ECU if the wrong diagram is used (especially with 12V vs. 5V pins).
Sensor ground return path. Never ground these to the chassis; they must loop back directly to the sensors to prevent electrical noise.
Oxygen sensor signal and oxygen sensor heater control. Step-by-Step Guide to Finding Your Specific 89661 Pinout : The sticker on the ECU case will have the full number (e
| Pin | Function | Typical Color | |-----|----------|----------------| | C1 | Diagnostic (TC/TE1) | Black/White | | C2 | Check engine light (CEL) | Green/Yellow | | C3 | MIL resistor (some models) | Not used | | C4 | EVAP purge VSV | Light Green/Black | | C5 | EVAP vent VSV | Green/White | | C6 | A/C clutch relay | Black/Blue | | C7 | Tachometer output | Black (single wire) | | C8 | +12V switched (IGN) | Black/Yellow | | C9 | Ground (ECU logic) | Brown | | C10 | Ground (ECU logic) | Brown | | C11 | CAN high (if equipped) | White | | C12 | CAN low (if equipped) | Red | | C13 | K-line (ISO 9141) | Violet/Yellow | | C14 | Immobilizer communication | Various | | C15 | Brake switch signal | Green/White | | C16 | Stop lamp monitor | Red/Black |
If you provide the full 10-digit part number (found on the metal casing of the unit), I can help find the exact pinout diagram.
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The part number is a generic Toyota prefix for Engine Control Units (ECUs) across nearly all models from the 1980s to the 2020s . Because the pinout varies wildly by engine type and year, you must match the five-digit suffix (e.g., 89661-3A080) to find the correct paper or digital diagram . Common 89661 Pinout Examples
While you must verify , many 89661 ECUs share a common logic. Below is a for Toyota ECUs from the 2000s (like 89661-06B40, -0D150, -33260). Use this to understand the function, but always confirm with your specific EWD.