| Pin # | Signal Name | Description | | --- | --- | --- | | 1-4 | Power supply (B+, B-, Ignition, and Ground) | Power and ground connections | | 5-8 | Sensor inputs (TPS, IAT, ECT, and MAP) | Throttle position, intake air temperature, engine coolant temperature, and manifold absolute pressure sensors | | 9-12 | Injector outputs ( Cyl 1-4) | Fuel injector control signals | | 13-16 | Ignition outputs (Cyl 1-4) | Ignition coil control signals | | 17-20 | Sensor inputs (CKP, CMP, O2, and Fuel Temp) | Crankshaft position, camshaft position, oxygen, and fuel temperature sensors | | 21-24 | Actuator outputs (Fuel Pump, Fan, and Wastegate) | Fuel pump, cooling fan, and turbocharger wastegate control signals | | 25-32 | Communication interfaces (CAN, LIN, and SPI) | Communication interfaces for diagnostics and programming | | 33-40 | Monitor and diagnostic outputs | Monitor and diagnostic signals for troubleshooting | | 41-48 | Sensor inputs (Vehicle Speed, Brake Switch, and Clutch Switch) | Vehicle speed, brake switch, and clutch switch inputs | | 49-56 | Outputs for accessories (Headlamp, Wiper, and Horn) | Outputs for controlling accessories | | 57-64 | Ground and shield connections | Ground and shield connections for various signals |
Often caused by a broken ground wire on the sensor circuit or an open signal pin at the ECU connector. isuzu 4hl1 ecu pinout
To work with the 4HL1 ECU, you need to understand its physical connectors. The ECU uses specific multi-pin connectors. The workshop manual mentions a few crucial connectors: | Pin # | Signal Name | Description
: Regulates fuel flow into the high-pressure pump. The workshop manual mentions a few crucial connectors:
A diagnostic trouble code (DTC) for "Injector Power Supply System Open Wiring" (e.g., DTC278) indicates an issue with the injector drive circuit. The ECU detects this when it finds an open circuit in the wiring between the injectors for cylinders #2 and #4 and their common ECU pin. The fix involves tracing the circuit from the injector connector back to the ECU to find the break.
The screen held steady at .
