A full Toyota ECU part number looks like:
89661-XXXXX (e.g., 89661-06A90, 89661-33240, 89661-52N10)
⚠️ Never assume pinout from the prefix alone. Always use the full 10-digit number on the ECU label.
The ECU usually has three connectors (often labeled E11, E12, E13 or simply arranged as rows).
| Suffix Example | Vehicle | Engine | |----------------|---------|--------| | 89661-0W590 | Toyota Camry 2007-2011 | 2AZ-FE (2.4L) | | 89661-33260 | Toyota Corolla 2005-2008 | 1ZZ-FE (1.8L) | | 89661-06A70 | Toyota Prius 2004-2009 | 1NZ-FXE (1.5L Hybrid) | | 89661-0P130 | Toyota RAV4 2006-2012 | 2AZ-FE | | 89661-30490 | Toyota Highlander 2008-2013 | 2GR-FE (3.5L V6) |
Critical: Always verify the full 10- or 12-digit part number on your ECU’s label before referencing any pinout.
The Toyota 89661 ECU is a robust engine management unit. Because the part number prefix covers a vast range of vehicles, it is imperative to verify the suffix (e.g., -35050) before applying a pinout diagram.
The pinout data provided in Section 3 applies to the most widely circulated variant (22R-E engines). For other variants, use the nomenclature guide in Section 4 combined with a vehicle-specific wiring diagram to safely test the pins. If the vehicle exhibits no-spark or no-injector pulse conditions, inspect the ECU internal capacitors, as this is the primary failure mode for the "89661" generation of Toyota electronics.
| Pin | Signal | Notes | |-----|----------------|-------| | B1 | +B (Main relay output) | Switched 12V to sensors | | B2 | +B2 (Injector power) | | | B3 | MREL (EFI main relay control) | ECU grounds to energize relay | | B4 | E01 (Power ground) | To engine block | | B5 | E02 (Power ground) | | | B6 | E03 | | | B7 | #10 (Injector 1) | ECU grounds injector | | B8 | #20 (Injector 2) | | | B9 | #30 (Injector 3) | | | B10 | #40 (Injector 4) | | | B11 | #50 (Injector 5 – V6) | | | B12 | #60 (Injector 6 – V6) | | | B13 | FC (Fuel pump control) | To fuel pump relay | | B14 | FPR (Fuel pressure regulator) | For returnless systems | | B15 | VSV (VVT oil control valve) | Variable valve timing solenoid | | B16 | EGR (EGR vacuum solenoid) | | | B17 | PRG (Purge VSV) | Evaporative emissions | | B18 | IAC1 (Idle air control – close) | | | B19 | IAC2 (IAC – open) | | | B20 | FAN (Cooling fan relay) | | | B21 | CEL (Check engine light) | To instrument cluster | | B22 | TC (Diagnostic test connector) | |
Most Toyota 89661 ECUs utilize a standardized physical form factor: four rectangular connectors. Toyota refers to these as Connector A, Connector B, Connector C, and Connector D (sometimes E on older units). However, not all ECUs use all four; a basic Corolla ECU might only use A, B, and C, while a Land Cruiser ECU will use all four.
Most 89661 ECUs use three 22-pin connectors (A, B, C) or four connectors (A, B, C, D). The pins are numbered embossed on the plug housing.
| Connector | Typical Color | Common Circuits | |-----------|---------------|------------------| | A (22-pin) | Gray or White | Injectors, ignition coils, power, grounds | | B (22-pin) | Gray | Sensors (TPS, MAP/MAF, ECT, IAT, CKP, CMP) | | C (16-22 pin) | Black or Blue | Solenoids (VVT, EGR, purge), fuel pump relay, CEL | | D (if present) | Black | Immobilizer, diagnostics (K-Line, CAN low/high) |
| Pin | Signal | Notes | |-----|----------------|-------| | C1 | CANH (CAN High) | OBD-II diagnostics | | C2 | CANL (CAN Low) | | | C3 | SIL (Serial data link) | Toyota proprietary | | C4 | TXCT (Transmit to diagnostic tool) | | | C5 | RXCT (Receive from diagnostic tool) | | | C6 | W (Warning light – MIL) | | | C7 | TACH (Tachometer output) | To cluster or diagnostic connector | | C8 | VSS (Vehicle speed output) | 4-pulse per revolution | | C9 | PSCT (Power steering signal) | Idle-up input | | C10 | STP (Stop lamp switch) | Brake pedal input | | C11 | IMI (Immobilizer signal) | From transponder key amplifier | | C12 | CODE (Immobilizer code line) | | | C13 | K-LINE (ISO 9141-2) | Older diagnostic | | C14 | L-LINE | | | C15 | IG+ (Ignition switch +12V) | Main ECU power | | C16 | E (Sensor ground return) | |