Case IH 17861 (F-651-04) - ECU – Engine Control Unit (ECU) / Engine Control Module (ECM): Short circuit of low side of injector in cylinder 1

The Engine Control Unit has detected that the low-voltage side of the wiring circuit for the fuel injector on cylinder 1 is shorted (either to the battery or to ground).

• VESTRUM CVX
• Steiger 400
• Steiger 450
• Steiger 500
• Steiger 540
• Steiger 580
• Steiger 620
• Magnum
• Farmall 40
• Farmall 45
• Farmall 50 CVT
• Axial-Flow 7130
• Axial-Flow 7240
• Axial-Flow 8240
• Axial-Flow 9240
• Austoft 9900

1. 1

   Visually inspect the engine wiring harness leading to the cylinder 1 injector for visible rubbing, chafing, or thermal events (melting/arcing).

2. 2

   Disconnect the cylinder 1 injector and the ECU connector. Use a multimeter to test the low-side wire of the injector circuit for a short to ground or a short to the battery.

3. 3

   Measure the resistance across the pins of the cylinder 1 injector to verify if the internal coil has shorted out.

4. 4

   If the wiring harness and the injector both test within specification, check for an unclassified error or a failed internal injector driver inside the Engine Control Unit itself.

1. 1

   Prepare machine for service

   Turn off the machine, ensure the key is removed, and disconnect the battery to prevent electrical damage.

2. 2

   Disconnect injector

   Locate the fuel injector for cylinder 1 on the engine block and disconnect its electrical pigtail connector.

3. 3

   Repair or replace wiring harness

   If diagnostic multimeter tests show the wiring harness is shorted to ground or battery, locate the damaged section of the harness. Repair the broken wires using proper soldering and heat-shrink techniques, or replace the engine wiring harness entirely.

4. 4

   Replace fuel injector

   If the injector coil is internally shorted, remove the high-pressure fuel lines and the hold-down clamp for the cylinder 1 injector. Remove the faulty injector and install a new OEM replacement, ensuring new seals/O-rings are used.

5. 5

   Replace or repair ECU

   If both the wiring and injector are good, the ECU must be replaced or sent out for repair due to a burnt-out internal low-side driver.

6. 6

   Reassemble components

   Reconnect all electrical connections and fuel lines.

7. 7

   Verify repair

   Reconnect the battery, connect a diagnostic service tool to the CAN bus diagnostic port, clear the fault codes, and run the engine to verify the repair.