ELBOW 3B6553 - Caterpillar

Introduction
The 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
Diagnostic connector
Electronic unit injectorsThe glow plugs are powered directly from the battery.ECM Power Supply
Illustration 1 g01334436
Schematic for ECM
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:
Battery
Disconnect switch
Ignition keyswitch
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 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.Power Supply for the Pressure Sensors
Illustration 2 g03347144
Schematic for the pressure sensors
The ECM supplies 5 VDC 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 g01201233
Schematic for the glow plugs