New Holland ENG 3763 – Engine Control Unit (ECU) / EDC: EDC - Level 2 Monitoring: Reported Under Voltage of Supply

The Engine Control Unit (ECU) continuously monitors the battery voltage supplied to it. This fault code is triggered when the voltage supply to the ECU drops below the minimum required threshold. This fault can frequently occur as a "ghost" code during a cold start if the battery voltage drops significantly while cranking.

• L220
• L316
• L318
• L320
• SR175
• CR9090
• CX8080
• CX8090
• T4 Series
• T5 Series
• T6 Series
• T7 Series

1. 1

   Check the resting battery voltage and perform a load test. A weak battery is the most common culprit, especially during cold cranking.

2. 2

   Determine if the code was thrown during a cold start (below 32 °F / 0 °C). If the machine starts and runs fine afterward, clear the code and see if it returns under normal operating temperatures.

3. 3

   Inspect the wiring harness from the battery to the EDC/ECU. Look for chafed wires, loose connections, or heavy corrosion at the battery terminals and chassis ground points.

4. 4

   Test the EDC Main Power Relay (Terminal 30 circuit). A sticking or failing relay can cause intermittent voltage drops to the controller.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable.

2. 2

   Clean Connections

   Clean all battery terminals, battery cables, and the main chassis ground with a wire brush. Reattach and tighten them to factory torque specifications.

3. 3

   Replace the Battery (If Applicable)

   If the battery failed the load test in the diagnostic phase, replace it with a unit meeting the OEM Cold Cranking Amps (CCA) requirement.

4. 4

   Replace the EDC Main Relay

   Locate the EDC main power relay in the fuse/relay box. If the relay contacts are pitted or it failed a bench test, pull the old relay and plug in the replacement.

5. 5

   Repair Harness (If Applicable)

   If wiring damage was found between the battery isolator and the EDC, splice and heat-shrink the damaged section or replace the affected harness segment.

6. 6

   Clear Codes

   Reconnect the battery, turn the key to the ON position, and use a diagnostic service tool (like the New Holland Electronic Service Tool) to clear the ENG 3763 code. Start the engine and verify the code does not return.