Case IH 19154 – DCU (Dosing Control Unit): UREA Pump speed | pump motor unplugged | P208B Reagent-pump not delivering

The system has detected an open circuit or a complete loss of communication/power to the DEF (Diesel Exhaust Fluid / Urea) pump motor. The control module monitors the pump motor speed deviation; if the difference between the commanded pump speed and the monitored pump speed exceeds a specific threshold (typically 300 rpm), the system determines the pump is not delivering reagent. This will cause the Selective Catalytic Reduction (SCR) system to shut down and the machine to eventually derate.

• Tier 4a
• Magnum series (e.g., 235–340 Series 4)
• Steiger series (e.g., 350–600)
• Puma
• Maxxum
• Farmall
• Axial-Flow series (e.g., 5130, 6130, 7130, 7240, 8240, 9240)

1. 1

   Visually inspect the wiring harness and electrical connector directly at the DEF pump (Supply Module) to ensure it is not unplugged, loose, or heavily corroded.

2. 2

   Load test the power and ground circuits to the DCU and the pump motor using a multimeter (do not rely on open-circuit voltages as they can be misleading).

3. 3

   Test the pump motor pins for continuity to check for an internal open circuit.

1. 1

   Repair Wiring

   If the diagnostic checks reveal a broken wire, corroded connector, or a bad ground, repair the harness or replace the pigtail connector.

2. 2

   Replace the DEF Pump

   If the wiring is intact and can carry a load, but the pump motor is internally open or seized, the DEF Supply Module must be replaced.

3. 3

   Clean the System

   Ensure the DEF tank and fluid are clean and free from contamination/crystallization, which is a leading cause of pump failure.

4. 4

   Programming

   Install the new DEF pump. Note: Replacement Bosch supply modules typically require programming/calibration to the vehicle's DCU using a dealer scan tool (EST) after installation.

5. 5

   Clear Codes

   Clear the fault codes and run a system prime/leak test via the diagnostic tool to ensure the new pump is delivering fluid correctly.