Case IH 17851 (F-651-05) - ECU – Engine Control Unit (ECU): Open load error of injector in cylinder 1

This fault code indicates an "open circuit" (open load) on the electrical circuit for the cylinder 1 fuel injector. The control module monitors the power stages of the injectors, and this code triggers when the system detects that the electrical connection to the cylinder 1 injector is broken. This is typically caused by a disconnected plug, a severed wire in the engine harness, or an internal failure (open solenoid) within the fuel injector itself.

• VESTRUM CVX
• Axial-Flow Combines (240 Series: 7240, 8240, 9240)
• Austoft 9900 Sugarcane Harvesters
• Tractors (Farmall, Puma, Magnum, Steiger, and Quadtrac series)

1. 1

   Verify Power Supply: Check that the tractor's battery power supply has not been improperly connected to an external power supply, which can cause voltage anomalies and false codes.

2. 2

   Visual Inspection: Inspect the wiring harness between the Engine ECU and the cylinder 1 fuel injector. Look for chafed wires, breaks, or a disconnected plug.

3. 3

   Connector Check: Disconnect the ECU and injector connectors. Check the pins for corrosion, moisture, or pushed-out terminals.

4. 4

   Resistance Test: Use a multimeter to measure the resistance across the cylinder 1 injector solenoid terminals. An infinite resistance reading confirms the injector has failed internally (open circuit).

5. 5

   Component Swap Test: Swap the cylinder 1 injector with the cylinder 2 injector. If the fault code changes to 17852 (Open load error of injector in cylinder 2), the injector is faulty. If the code remains 17851, the issue is in the wiring harness or the ECU.

1. 1

   Disconnect the machine's battery power

   to prevent electrical shorts.

2. 2

   Gain access to the fuel injectors.

   Depending on the specific FPT engine (e.g., NEF vs. Cursor), this may require removing the engine valve cover.

3. 3

   Disconnect the electrical connector

   from the cylinder 1 fuel injector.

4. 4

   Repair the broken wires or replace the injector wiring harness/pigtail.

   If the diagnostic checks revealed a wiring issue.

5. 5

   Thoroughly clean the area around the injector

   to prevent debris from entering the cylinder if the injector is faulty.

6. 6

   Remove the high-pressure fuel line

   connected to the injector.

7. 7

   Remove the injector hold-down clamp and carefully extract the injector

   from the cylinder head.

8. 8

   Install the new OEM fuel injector

   ensuring new O-rings and sealing washers are used.

9. 9

   Reinstall the hold-down clamp

   and torque to the manufacturer's specifications.

10. 10

    Reconnect the high-pressure fuel line and the electrical connector.

11. 11

    Reinstall the valve cover with a new gasket

    (if removal was required).

12. 12

    Reconnect the battery.

13. 13

    Program the new injector's IMA (Injector Quantity Adjustment) code into the Engine ECU

    using a diagnostic tool. The IMA code is printed directly on the new fuel injector.

14. 14

    Bleed the fuel system if required, clear the fault codes, and test run the engine

    to verify the repair.