Case IH F-5839-15 - ECU – Engine ECU or Aftertreatment / DEF Control Module (DCU): SCR Inducement: Warning, triggered by Reagent Consumption fault

The system has detected an abnormality in the consumption rate of the Diesel Exhaust Fluid (DEF/AdBlue). The system is either consuming less DEF than expected for the current engine load, or there is a deviation in the dosing quantity. The '15' indicates a warning level (least severe), but if left unaddressed, it will escalate to Level 1 (torque reduction) and eventually Level 3 (creep mode/severe derate).

• MAGNUM AFS Connect
• Steiger
• Magnum
• Puma
• Farmall
• Maxxum
• Vestrum
• Luxxum
• Axial-Flow 5140
• Axial-Flow 6150
• Axial-Flow 7150
• Axial-Flow 8230
• Axial-Flow 9230
• Patriot 2250
• Patriot 3240
• Patriot 3340
• WD series windrowers

1. 1

   Check for concurrent faults: Read all active codes. Diagnose any SCR-related faults (e.g., DEF pressure, NOx sensor plausibility, or DEF temperature) first, as they can trigger the 5839 consumption fault as a secondary symptom.

2. 2

   Perform a visual inspection: Inspect the DEF tank, lines, pump, and injector for physical leaks, damage, or white crystallized DEF buildup.

3. 3

   Check the suction tube: Inspect the DEF suction tube assembly inside the tank for hairline cracks (especially on models like the 9230 combine) which can draw air into the system and cause the pump to lose prime.

4. 4

   Perform actuator and dosing tests: Use the diagnostic tool (e.g., CNH EST) to run a 'DEF Leak Test' and a 'Test of DEF metering amount' to verify if the pump and injector can deliver the correct fluid volume.

5. 5

   Inspect wiring: Check the wiring harnesses connecting the DEF pump, DEF injector, and Engine ECU for short circuits, open circuits, or high resistance.

1. 1

   Resolve Fluid Issues

   Ensure the DEF tank is filled with fresh, uncontaminated, ISO-compliant fluid. Contaminated DEF can clog internal passages.

2. 2

   Clean or Replace the Injector

   If the DEF injector (dosing valve) is blocked by crystallized DEF, remove it from the exhaust pipe. Clean the nozzle if possible; if the blockage is severe or internal, replace the injector.

3. 3

   Replace the DEF Filter

   If the system is starving for fluid, replace the DEF filter cartridge located in the supply pump module. This should be done as part of routine maintenance to ensure optimal SCR performance.

4. 4

   Address Air Leaks

   If the system loses prime during operation but works fine in the shop, replace the DEF tank suction unit/header, as it likely has a stress crack drawing in air.

5. 5

   Replace the DEF Pump

   If the pump fails the diagnostic leak or dosing tests, or cannot build the required pressure (up to 9 bar/130 psi), replace the DEF Supply Module (pump). Note: A new DEF pump module will require programming/calibration to the vehicle's ECU using the diagnostic tool.

6. 6

   System Reset

   After repairs, clear the fault codes and perform an SCR system reset / inducement reset via the diagnostic tool to restore full engine power.