Case IH F-5435-05 - ECU – Engine Control Unit (ECU): DEF/AdBlue supply module pump motor open load failure

The control module has detected that the electrical circuit controlling the Diesel Exhaust Fluid (DEF) pump motor is incomplete, broken, or disconnected, preventing the pump from operating and dosing fluid into the SCR system.

• MAGNUM AFS Connect
• 240 Series Combines (5130, 6130, 7130, 7230, 8230, 9230)
• Magnum Tractors (180 through 370)
• Maxxum Tractors (110 through 140)
• Puma Tractors (130 through 215)
• Steiger Tractors (350 through 600)
• Farmall Tractors (95A, 100C, 110C)
• Patriot Sprayers 4430
• Titan Sprayers 3030, 3530, 4030, 4530
• Farmlift Telehandlers 632, 635, 735, 742, 935
• 1150M Crawler Dozers
• 9900 Sugar Cane Harvesters

1. 1

   Visually inspect the harness leading to the DEF supply module for damaged, chafed, or broken wires

2. 2

   Inspect for loose machine grounds (earths) and loose connector pins

3. 3

   Check for debris or water intrusion inside the connector terminals (often caused by pressure washing or poor sealing)

4. 4

   Test the control circuit between the ECU and the DEF pump for continuity to determine if the open circuit is in the wiring or internal to the pump motor

1. 1

   Preparation

   Stop the engine and let it cool completely before starting work. Do not start the engine during the service procedures. Turn off the ignition switch.

2. 2

   Cleaning

   Ensure the surrounding area is completely clean of dust and dried white urea crust before opening any lines or caps. If you need to flush the external housing face, use only clean distilled water to safeguard the internal high-pressure fluid loops.

3. 3

   Wiring Repair (If Applicable)

   If diagnostics revealed water intrusion or broken wires, clean the terminals, repair the harness, and ensure weather seals are intact.

4. 4

   Module Replacement

   If the pump motor has failed internally (open load), the DEF Supply Module must be replaced. Disconnect the electrical harness and fluid lines, unbolt the module from its bracket, and install the new unit.

5. 5

   Filter Maintenance

   When replacing the pump or servicing the system, replace the DEF filter element. Always use the specialized tool included in the filter kit to carefully extract the old filter element to prevent scratching the inner walls of the pump housing reservoir.

6. 6

   Code Clearing

   Turn on the ignition switch without starting the engine. Use a trouble diagnosis scan tool (Electronic Service Tool) to observe and clear the F-5435-05 / P20C9 DTCs.