Engine Operation 46 UENR0623-02 ECM Power Supply Illustration 42 g02720990 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 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 main relay will remain energized for a time period after the keyswitch has been turned to the OFF position.
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.