C4.4 Engines for Caterpillar Built Machines Power Sources Caterpillar


Power Sources
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C4.4 Engines for Caterpillar Built Machines [UENR4524]
OPERATOR STATION
C4.4 Engines for Caterpillar Built Machines Power Sources
1.1. Introduction
2.1. ECM Power Supply
3.1. Power Supply for the Pressure Sensors
4.1. Power supply for the Glow plugs

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

  • Diagnostic connector

  • Electronic unit injectors

The glow plugs are powered directly from the battery.

ECM Power Supply



Illustration 1g01334436
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

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.

Power Supply for the Pressure Sensors



Illustration 2g03538938
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 3g01360925
Schematic for the glow plugs