New Holland ENG 3063 – Engine Control Unit (ECU): Cylinder 1 - Injector Cable Short Circuit (High Side to Ground)

This fault code indicates that the engine control system has detected a short circuit to ground on the high-voltage side of the electrical circuit supplying the fuel injector for Cylinder 1. This prevents the injector from firing correctly, leading to a misfire, rough running, or engine derate.

• T5 Series (T5.95, T5.105, T5.115, T5.120, T5.130, T5.140)
• T6 / T6000 Series (T6010 through T6090)
• T7 / T7000 Series
• T8 Series
• T9 Series (T9.530, T9.645)
• TSA Series (TS125A, TS135A)
• CR9090
• CX8080
• CX8090
• B110B Tractor Loader Backhoes
• W50C to W80C Wheel Loaders
• E-Series Excavators

1. 1

   Inspect the engine wiring harness routing from the ECU to the Cylinder 1 injector for chafing, melted insulation, or pinched wires where the harness touches the engine block or valve cover.

2. 2

   Disconnect the harness at the ECU and at the Cylinder 1 injector. Use a multimeter to test the high-side wire for continuity to ground. If there is continuity, the harness is shorted.

3. 3

   Test the internal resistance of the Cylinder 1 injector coil to check for an internal short. Compare the resistance reading to a known good injector (e.g., Cylinder 2).

4. 4

   If the wiring and injector test fine, check the injection signals coming directly from the ECU pins to rule out an internal short within the engine controller itself.

1. 1

   Disconnect Power

   Disconnect the machine's battery to prevent electrical spikes during repair.

2. 2

   Isolate the Fault

   Based on the diagnostic checks, determine if the fault is in the wiring, the injector, or the ECU.

3. 3

   Repair/Replace Wiring

   If the short is in the wiring, either repair the damaged section of the wire using OEM-approved splicing techniques and heat shrink, or replace the entire fuel injector wire harness.

4. 4

   Replace Injector

   If the injector coil is internally shorted, remove the high-pressure fuel line, unbolt the injector hold-down clamp, and extract the Cylinder 1 injector. Install a new injector with new O-rings and copper sealing washers. Torque to OEM specifications.

5. 5

   Replace ECU

   If the EDC7 controller is internally shorted, replace the ECU. (Note: A new ECU will require dealer-level programming/flashing to match the machine).

6. 6

   Clear Codes

   Reconnect the battery, turn the key on, and use a diagnostic scan tool (like the CNH Electronic Service Tool) to clear the inactive ENG 3063 fault code. Run the engine to verify the fix.