New Holland ENG 3075 – Engine Control Module (ECM / ECU): Cylinder 6 - Injector Cable Short circuit (High Side to Ground)

The engine's control module has detected a short circuit to ground on the high-voltage (supply) side of the electrical circuit for the cylinder #6 fuel injector, which typically results in a cylinder misfire, rough engine operation, and the engine entering a derated limp mode.

• T7 series
• T8 series
• T9 series
• Magnum 215
• Magnum 235
• Magnum 335
• Magnum 340
• Wheel loaders
• Excavators

1. 1

   Check for multiple injector codes (external harness cause): Verify if other injector codes are present, which indicates the main engine wiring harness is likely rubbing against the engine block or chassis.

2. 2

   Inspect external harness (external harness cause): Inspect the wiring harness running from the ECM to the cylinder head pass-through connector for chafing, melted insulation, or pinched wires.

3. 3

   Isolate the short: Disconnect the engine harness at the cylinder head and measure the resistance of the cylinder 6 high-side pin to a known good ground. If the short remains on the ECM side, the external harness is faulty. If it disappears, the issue is under the valve cover.

4. 4

   Inspect internal harness (internal harness cause): Remove the valve cover and inspect the internal injector wiring harness for brittle or cracked insulation.

5. 5

   Test the injector coil (injector failure cause): Disconnect the wires from the cylinder 6 injector. Test resistance across the coil (OEM spec 0.56 to 0.57 Ohms) and check for continuity between the pins and the metal injector body. Continuity to the body means the injector is internally shorted.

1. 1

   Disconnect Power

   Disconnect the negative battery terminal to prevent ECM damage.

2. 2

   Access the Wiring

   Based on your diagnostic isolation, locate the shorted section of the harness.

3. 3

   External Harness Repair

   If the external harness is damaged, repair the wire using OEM-approved heat-shrink butt connectors, or replace the entire engine wiring harness if the damage is extensive.

4. 4

   Internal Repair

   Clean the area around the valve cover and remove it. If the internal harness is shorted, unbolt and replace the under-cover injector wiring harness. If the cylinder 6 injector is internally shorted, remove the high-pressure fuel line (tube) feeding cylinder 6, remove the injector hold-down clamp, extract the faulty injector, and clean the injector cup in the cylinder head.

5. 5

   Reassembly

   Install the new injector (if required) with new O-rings and copper sealing washers. Install a new high-pressure fuel tube (these are generally single-use items that can leak if reused). Torque all fittings to OEM specifications. Reinstall the valve cover using a new top gasket set.

6. 6

   Finalize

   Reconnect the battery, clear the fault codes using a diagnostic scan tool, and test run the engine to ensure there are no fuel leaks and the misfire is resolved.