EDGE 2199489 - Caterpillar

Introduction
The application supplies power to the ECM. The ECM powers the following components:
All sensors on the engine and the clean emissions module
The Nitrogen Oxide (NOx) sensors
The suction control valve for the fuel injection pump
The solenoid for the wastegate
Diagnostic connector
Electronic unit injectorsThe glow plugs are powered directly from the battery.The engine ECM also controls power to the DEF system. The engine ECM does not power the DEF system.ECM Power Supply
Illustration 1 g03167497
Typical example
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 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 g03167376
Schematic for pressure sensors
The ECM supplies 5 VDC through the J2 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 g03167499
Typical example
Power Supply for the Pump Electronics Tank Unit (PETU)
Illustration 4 g03402800
Typical example of a schematic diagram of the Pump, Electronics, and Tank Unit (PETU)