Output signal to the EFI relay to provide main power.
Before you start probing wires, follow this flowchart: toyota 89661 ecu pinout
Do not assume pin positions by color coding. Toyota changes wire colors between model years and even between sedan vs. wagon versions of the same car. Output signal to the EFI relay to provide main power
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. and engine code