The Ultimate Guide to the Toyota 89661 ECU Pinout: Wiring, Diagnostics, and Troubleshooting

Searching for the engine code (e.g., "1ZZ-FE pinout") alongside the 89661 number often yields better results than the part number alone. Could you provide the full 10-digit part number engine and year of your Toyota so I can find the exact wiring diagram?

• Use dedicated fused power for additional loads.
• Avoid tying into critical ECU power pins without understanding load and wake behaviors.
• Keep CAN/LIN topology intact; termination resistors should remain at network ends.

Using a Digital Multimeter (DMM):