Case IH 3075 (DTC 6526) – Engine Control Unit (ECU) / Engine Control Module (ECM): Short circuit error of injector in cylinder 6

The engine's control system has detected an electrical short circuit (often logged as HSD to LSD - High Side Drive to Low Side Drive) in the wiring harness or the internal solenoid of the fuel injector for cylinder number 6.

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7230, 8230, 9230, 7240, 8240, 9240)
• Puma series
• Magnum series
• Steiger series
• Maxxum series
• Patriot series

1. 1

   Check for Bank Faults: Determine if fault 3218 (DTC 7216) - "Injection bank 2 short circuit failure" is also present. The ECU groups injectors into banks; a severe short in cylinder 6 can cause the ECU to disable the entire bank to protect the circuitry.

2. 2

   Check for Accompanying Codes: Look for codes 3083 (DTC 6326 - cylinder 5) or 3067 (DTC 6726 - cylinder 4). If multiple codes are present, the issue is highly likely to be a chafed main wiring harness rather than a single failed injector.

3. 3

   Harness Inspection: Visually inspect the wiring harness running from the Engine ECU to the cylinder 6 injector. Look for rubbed-through insulation, pinched wires under brackets, or melted shielding.

4. 4

   Resistance Test: Disconnect the electrical connector at the cylinder 6 injector. Measure the resistance across the two pins on the injector itself using a multimeter. If the resistance is out of specification (typically reading near 0 ohms for a dead short), the injector solenoid has failed internally.

1. 1

   Disconnect Power

   Turn off the battery disconnect switch to prevent accidental ECU damage or electrical shock (these are high-voltage injector circuits).

2. 2

   Gain Access

   Depending on the engine model (especially Cursor engines), remove the engine valve cover to access the fuel injectors and internal wiring harness.

3. 3

   Isolate the Circuit

   Disconnect the electrical pigtail from the cylinder 6 injector.

4. 4

   Test the Harness

   With the injector unplugged, turn the key to the ON position (do not start) and use a diagnostic tool to see if the short circuit code changes to an "Open Circuit" code (e.g., P0206 13). If it changes to open, the wiring is good and the injector is the culprit. If the short circuit code remains, the wiring harness is shorted together and must be repaired or replaced.

5. 5

   Remove the Injector

   If the injector is faulty, clean the area around the injector thoroughly to prevent debris from entering the cylinder. Remove the high-pressure fuel line and the injector hold-down clamp/bolt.

6. 6

   Extract and Replace

   Pull the injector from the cylinder head. Install the new injector with new O-rings and a new copper sealing washer at the tip.

7. 7

   Reassembly

   Torque the hold-down clamp and high-pressure fuel lines to OEM specifications. Reconnect the electrical harness and reinstall the valve cover.

8. 8

   Clear Codes

   Reconnect battery power, bleed the fuel system if required by the specific engine manual, and use a diagnostic tool to clear the fault codes.