New Holland NH 3073 – Engine Control Unit (ECU): Injector solenoid valve Cylinder 6 - SOURCE HIGH

This fault code indicates an electrical short circuit on the source voltage circuit for the Cylinder 6 fuel injector. This prevents the injector from firing properly, usually resulting in an engine misfire, derate, or limp mode.

• T6 Series
• T7 Series
• T8 Series
• T9 Series
• CR Series
• CR8.90
• CR9.90
• Magnum
• Maxxum
• Puma
• Steiger

1. 1

   Inspect the engine wiring harness routing from the Engine ECU to the Cylinder 6 injector for chafed insulation, melted wires, or pinch points against the engine block or valve cover.

2. 2

   Disconnect the Cylinder 6 injector connector and the main ECU harness connector. Inspect for moisture, oil intrusion, corrosion, or bent pins.

3. 3

   With the harness disconnected at both ends, use a multimeter to test the Cylinder 6 injector wires for a short to battery voltage (12V/24V) and a short to ground.

4. 4

   Measure the resistance across the pins of the Cylinder 6 injector itself and compare the reading to a known good injector (e.g., Cylinder 5) to determine if the injector solenoid is internally shorted.

1. 1

   Disconnect Battery

   Turn off the machine and disconnect the negative battery terminal to prevent ECU damage during electrical work.

2. 2

   Repair/Replace Wiring

   If the diagnostic tests revealed a short in the wiring harness, repair the damaged section of the wire using heat-shrink butt connectors, or replace the injector harness pigtail. If the main engine harness is severely degraded, replace the entire engine wiring harness.

3. 3

   Replace Injector

   If internally shorted: Remove the valve cover (if the injectors are located under the cover). Remove the high-pressure fuel line to Cylinder 6 and cap fuel lines to prevent contamination. Remove the injector hold-down clamp and extract the Cylinder 6 injector. Install the new injector with a new copper crush washer and O-rings. Torque the hold-down bolt and high-pressure lines to OEM specifications.

4. 4

   Reassemble and Bleed

   Reinstall any removed covers. Reconnect the battery. Prime the fuel system to bleed out air.

5. 5

   Clear Codes

   Connect a diagnostic tool (such as CNH Electronic Service Tool) to clear the inactive NH 3073 fault code from the ECU memory. Test run the engine to verify the misfire is gone and the code does not return.