Case IH 19298 – DCU (Dosing Control Unit): UREA pressure too low at system start / Reagent pump not delivering.

The Selective Catalytic Reduction (SCR) system is unable to build adequate Diesel Exhaust Fluid (DEF/Urea) pressure when the system initializes. The system monitors the pump motor speed deviation; if the difference between the commanded pump speed and the monitored pump speed exceeds 300 RPM, this DTC sets, the SCR system shuts down, and the machine will eventually derate.

• Tier 4a
• Tier 4b
• Case IH Magnum Series: 235, 260, 290, 315, 340, 370, 380
• Case IH Steiger Series: 350, 400, 450, 500, 550, 600

1. 1

   Verify DEF fluid level and quality, ensuring the tank is not empty and fluid is not frozen

2. 2

   Inspect the DEF supply line and suction tube for leaks, restrictions, breaks, or kinks

3. 3

   Check the DEF inline filter for plugging or clogging

4. 4

   Test the power and ground circuits to the DCU using a multimeter under load (open-circuit voltages can hide a bad ground or weak power supply)

5. 5

   Perform the Urea Dosing System Test (UDST) using the Case IH Electronic Service Tool (EST) to verify pump operation and pressure sensing accuracy

1. 1

   Visual & Physical Inspection

   Trace all DEF lines from the tank to the dosing pump. Repair or replace any damaged or kinked lines.

2. 2

   Filter Replacement

   Remove the DEF inline filter. If it is dirty or plugged, replace it.

3. 3

   Electrical Verification

   Confirm the DCU is receiving proper voltage and has a solid ground under load.

4. 4

   Pump Replacement

   If the lines are clear, the filter is clean, the fluid is good, and the wiring passes load testing, the DEF supply pump (reagent pump) is likely too weak due to internal leakage or motor failure. Remove and replace the DEF Dosing Pump/Module.

5. 5

   Programming

   Be aware that a new DEF dosing module may need to be programmed/calibrated to the vehicle's DCU after installation.

6. 6

   Verification

   After repairs are made, use the EST to run the Urea System Dosing Test to verify the system can now build adequate pressure. Clear the fault codes.