The engine supplies power to the ECM. The ECM powers the following components:
- All sensors on the engine
- The suction control valve for the fuel injection pump
- The solenoid for the wastegate
- Diagnostic connector
- Electronic unit injectors
The glow plugs are powered directly from the battery.
The power supply to the ECM and the system is drawn from the 24 V or the 12 V battery. The power supply for the ECM has the following components:
- Disconnect switch
- Ignition keyswitch
- Ground bolt
- ECM connector
- Machine interface connector
The Schematic for the ECM shows the main components for a typical power supply circuit. Battery voltage is normally connected to the ECM. The input from the ignition keyswitch turns on the ECM.
The wiring harness can be bypassed for troubleshooting purposes.
The display screen on the electronic service tool can be used in order to check the voltage supply.
Schematic for pressure sensors|
The ECM supplies 5 DC volts through the ECM connector to each sensor. The power supply is protected against short circuits. A short in a sensor or a wiring harness will not damage the ECM.
Note: Refer to Systems Operation, Testing, and Adjusting, "Electronic Control System" for more information on the engine sensors.