Case IH 19157 – DCU (Dosing Control Unit): UREA Pump speed | Hall sensors defect | P208B Reagent-pump not delivering

The control module has detected a defect in the Hall sensors inside the UREA (DEF) pump motor, or a significant deviation in the pump's operating speed (e.g., difference between commanded and monitored speed exceeds 300 rpm). The system determines the pump is not delivering reagent properly, causing the SCR system to shut down and eventually leading to an engine derate.

• Tier 4a
• Case IH Steiger & Quadtrac 350, 370, 400, 450, 470, 500, 540, 550, 580, 600, 620
• Case IH Magnum 235, 280, 310, 340, 380 (Series 4)
• Case IH Puma 170, 185, 210
• Case IH Rowtrac 350, 400, 450, 500

1. 1

   Perform a wiring and ground load test on the power and ground circuits to the DCU and the DEF pump to ensure they can carry the necessary current without dropping voltage.

2. 2

   Inspect the DEF pump motor wiring harness and connectors for unplugged, corroded, or damaged pins.

3. 3

   Ensure the DEF fluid is clean and free from contamination, as debris can block the pump or damage internal components.

1. 1

   Clear and Retest

   Clear the fault codes and cycle the key to see if the code returns immediately. The system monitors the pump motor speed deviation on each key cycle.

2. 2

   Replace the DEF Pump

   If a Hall sensor defect is confirmed, replace the entire DEF Dosing Pump (Supply Module) because the Hall sensors are internal to the DEF pump motor and are not serviced separately.

3. 3

   Reprogramming

   Install the new DEF pump module. A new Bosch/OEM replacement module must be programmed/calibrated to the vehicle's DCU after installation for the system to recognize it and function correctly.

4. 4

   System Reset

   After programming, run the machine to ensure the SCR system initializes, the pump primes, and the engine derate is lifted.