Case IH F-656-05 - ECU – Engine Control Unit (ECU): Open load error of injector in cylinder 6

The electrical current traveling to the electronic fuel injector for cylinder #6 is lower than expected, or there is a complete open circuit detected. Because the injector cannot fire properly, the engine will run rough, misfire, and likely be forced into a derated power state or low idle.

• MAGNUM AFS Connect
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Steiger
• Magnum
• Puma
• Maxxum
• CVX series
• Austoft 9900 sugarcane harvesters
• Patriot series (3230, 3330)

1. 1

   Check if the tractor's battery has been connected to an external power supply (like a jump starter). Disconnect it and test for normal operation, as voltage irregularities can trigger false open load codes.

2. 2

   Inspect the wiring harness between the Engine Module ENG (A15) and the electronic injector for cylinder 6 (Y320-6 or Y-066) for chafed wires, disconnected plugs, or corrosion.

3. 3

   Unplug the cylinder 6 injector and test the internal resistance of the injector coil using a multimeter to determine if the open circuit is inside the injector itself or in the wiring harness.

1. 1

   Power Down

   Turn off the machine and disconnect the negative battery terminal to prevent electrical shorts.

2. 2

   Access the Injector

   Remove the engine valve cover or injector access panels to reach the fuel injector for cylinder #6 (typically the rearmost cylinder on an inline-6 engine).

3. 3

   Inspect and Clean

   Disconnect the electrical connector at the injector. Inspect the pins for corrosion, bent terminals, or pushed-out pins. Clean with contact cleaner if necessary.

4. 4

   Trace the Circuit

   If the injector tests within specification, trace the wiring harness back to the ECU. Repair any broken wires or replace the injector harness if internal breaks are found.

5. 5

   Replace the Injector

   If the injector coil is open (infinite resistance), the injector has failed internally. Remove the high-pressure fuel line, unbolt the injector hold-down clamp, and extract the injector. Install the new injector with new O-rings and copper sealing washers.

6. 6

   Reassemble and Clear Codes

   Reinstall the fuel lines (torquing to OEM spec) and valve cover. Reconnect the battery, use a diagnostic scan tool to clear the F-656-05 code, and run the engine to verify the misfire is resolved. (Note: Depending on the engine generation, a new injector's QR calibration code may need to be programmed into the ECU).