New Holland NH 3077 – Engine ECU (Electronic Diesel Control / EDC): Injector solenoid valve Cylinder 2 - SOURCE HIGH

A short circuit on the injector cable for Cylinder 2 (Short circuit Low Side to Battery), indicating unexpectedly high voltage on the circuit controlling the fuel injector for the second cylinder, preventing it from firing correctly.

• New Holland T7 Series Tractors
• New Holland T8 Series Tractors (e.g., T8.275, T8.390)
• New Holland T9 Series Tractors (e.g., T9.435)
• New Holland CR Series Combines (e.g., CR7090)
• New Holland Wheel Loaders
• New Holland TLB models

1. 1

   Visual Inspection: Inspect the engine wiring harness running from the Engine ECU to the Cylinder 2 injector for chafed wires, melted insulation, or pinch points.

2. 2

   Connector Check: Disconnect the harness at the Cylinder 2 injector and at the Engine ECU. Inspect pins for corrosion, moisture, or bent terminals.

3. 3

   Multimeter Testing (Harness): With the battery connected but the ECU and injector unplugged, check the Cylinder 2 injector low-side wire for continuity to battery voltage. Voltage present indicates a shorted harness.

4. 4

   Multimeter Testing (Injector): Test the resistance across the terminals of the Cylinder 2 injector solenoid to check for an internal short.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical damage during the repair.

2. 2

   Access the Components

   Remove any engine covers or valve covers necessary to access the Cylinder 2 fuel injector and the engine wiring harness.

3. 3

   Repair/Replace Harness

   If the diagnostic tests revealed a short in the wiring, repair the damaged section of the wire using proper splicing techniques and heat shrink. If the harness is severely degraded, replace the entire Engine Wire Harness.

4. 4

   Replace Injector

   If the harness tested fine but the injector solenoid is internally shorted, remove the high-pressure fuel line and retaining clamp for Cylinder 2. Extract the faulty injector and install the new replacement, ensuring the nozzle washer/O-ring is seated correctly. Torque the hold-down clamp and fuel lines to OEM specifications.

5. 5

   Reassembly

   Reconnect the wiring harness to the injector and the ECU. Reinstall any removed covers.

6. 6

   Restore Power & Clear Codes

   Reconnect the battery. Connect a compatible diagnostic tool (such as CNH EST, Jaltest, or TEXA) to the machine's diagnostic port to clear the NH 3077 fault code.

7. 7

   Test Run

   Start the engine and verify that it runs smoothly without derating and that the fault code does not return.