PLATE 1772491 - Caterpillar

Introduction (Power Supplies)
The C4.4 engine supplies power to the ECM. The ECM powers the following components:
All sensors on the engine
The solenoid for the fuel Injection Pump
The solenoid for the Wastegate (optional)
Diagnostic connector
Electronic unit injectorsThe glow plugs are powered directly from the battery.ECM Power Supply
Illustration 1 g01336367
Schematic for ECM
The power supply to the ECM and the system is drawn from the 24 volt or the 12 volt battery. The power supply for the ECM has the following components:
Battery
Disconnect switch
Key start switch
Fuses
Ground bolt
ECM connector
Machine interface connectorThe 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 key start switch 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. Power Supply for the Pressure Sensors
Illustration 2 g01336369
Schematic for pressure sensors
The ECM supplies 5.0 0.2 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 cause damage to the ECM.Power supply for the Glow plugs
Illustration 3 g01360925
Schematic for the glow plugs