Case IH 3075 – Engine Control Module (ECM) / Electronic Diesel Control (EDC): Cylinder 6 - Injector Cable Short circuit (High Side to Ground) or (High Side to Low Side)

The engine controller has detected that the voltage supply wire (high side) for the cylinder 6 fuel injector is shorting out, either directly to the chassis ground or to the return wire (low side). This prevents the injector from firing properly, resulting in a misfire, rough running, and power loss.

• Steiger T4B
• Case IH Magnum 235 - 340 (Series 4)
• Case IH Steiger 350 - 600
• Case IH Optum
• Case IH Puma
• Case IH Maxxum

1. 1

   Visually inspect the engine wiring harness routing to the cylinder 6 injector for chafing, rubbed-through insulation, or melted wires, particularly near hot exhaust components or sharp metal brackets.

2. 2

   Disconnect the wiring harness at the cylinder 6 injector to isolate the short.

3. 3

   Use a multimeter to measure the resistance across the pins of the cylinder 6 injector. If resistance is near zero ohms, the injector solenoid is internally shorted.

4. 4

   If the injector tests good, check the wiring harness from the ECM to the injector connector for continuity to ground on the high-side wire to confirm a harness short.

1. 1

   Turn off the machine's master battery disconnect switch to prevent electrical arcing or ECM damage.

2. 2

   Gain access to the cylinder 6 injector.

   Depending on the specific FPT engine displacement (e.g., 8.7L Cursor 9 or 12.9L Cursor 13), this may require removing the engine valve cover to access the internal injector harness and the injector itself.

3. 3

   If the diagnostic tests pointed to the wiring harness, repair the chafed section of the wire using proper soldering and heat-shrink techniques, or replace the entire injector wiring harness if the damage is extensive or internal to a molded connector.

4. 4

   If the diagnostic tests pointed to the injector, remove the cylinder 6 fuel injector hold-down clamp, extract the faulty injector, and install a new OEM fuel injector with new O-rings and copper sealing washers.

5. 5

   Reinstall the valve cover with a new gasket (if removed).

6. 6

   Reconnect the battery, connect an electronic service tool (such as the CNH EASy tool or Jaltest), and clear the inactive 3075 fault code.

7. 7

   Start the engine and verify that the misfire is gone and the code does not return.