Engine load signals. PIM stands for Pressure Intake Manifold (MAP sensor); VG stands for Voltage Generation (MAF sensor).
Attach the BATT pin to the positive 12V terminal.
Check if the diagram you are using shows the pinout from the wire side (looking at the back of the plug) or the board side (looking directly at the metal ECU pins). Mistaking these views flips the layout horizontally. toyota 89661 ecu pinout
The Ultimate Guide to Toyota 89661 ECU Pinouts: Identification, Wiring, and Troubleshooting
Crankshaft Position Sensor signal (essential for engine timing and RPM calculation). G1 / G2 / G+: Camshaft Position Sensor signals. THA: Intake Air Temperature (IAT) sensor input. THW: Engine Coolant Temperature (ECT) sensor input. VTA / VTA2: Throttle Position Sensor (TPS) signal voltage. Engine load signals
Because "89661" applies to hundreds of different board layouts, finding the correct wiring diagram requires decoding your specific part number suffixes and identifying your plug configurations. This comprehensive guide covers how to read Toyota ECUs, common pin functions, and troubleshooting steps. Understanding the Toyota 89661 Part Number System
Power grounds for high-current components like fuel injectors and coil igniters. Ignition and Fuel Control Check if the diagram you are using shows
| | Function | Signal | Notes | |---|---|---|---| | E9-3 | BAT | Constant 12V | Memory keep-alive | | E9-1 | B+ | Switched 12V | Main power | | E9-9 | IGSW | Ignition 12V | Key-on signal | | E12-7 (E9-18) | K-Line | ISO 9141 | Diagnostic line | | (ECU pin A) | NE+ / NE- | VR sensor | ~1-3Vpp while cranking | | (ECU pin G) | G2+ / G2- | Hall/VR | 0-5V square wave | | (ECU pin VG) | VG | 0.9-1.2V | MAF signal | | (ECU pin THW) | THW | NTC thermistor | Variable resistance | | (ECU pins B4) | KNK | Knock sensor | AC signal |
Regardless of the year, Toyota maintains a highly consistent naming convention for the labels printed directly on the ECU circuit board (PCB). If you open the metal casing of an 89661 ECU, you will find these abbreviations stamped next to the solder joints. Power Supply & Ground
Older ECUs use 2 or 3 yellow/grey plastic plugs. Mid-90s to 2000s models use 4 or 5 row connectors. Modern OBD2 ECUs often use large dual-block connectors with locking levers.
Modern 89661 modules rely heavily on multiplexing. Key inputs like vehicle speed, air conditioning requests, and instrument cluster data are no longer sent via dedicated single wires. Instead, they travel across CAN-H (Controller Area Network High) and CAN-L (Controller Area Network Low) communication lines. Step-by-Step Bench Wiring for Diagnostics or Tuning