The prefix "89661" is Toyota's master code for its Engine Control Module (ECM), also known as the Powertrain Control Module (PCM). The full part number on the sticker, such as 89661-XXXXX , is critical for identification as the suffix letters and numbers specify exactly which vehicle, engine, and transmission the unit is designed for.
1JZ-GTE VVTi, 2JZ-GTE VVTi, 3S-GE Beams, 1ZZ-FE, 2AZ-FE. toyota 89661 ecu pinout
You can find scanned factory manuals on forums. Use specific search strings: The prefix "89661" is Toyota's master code for