New Holland DCU 19155 – DCU: UREA Pump speed – pump motor blocked – Reagent-pump

The system has detected that the DEF (Diesel Exhaust Fluid) / Urea supply pump motor is physically or electrically blocked and cannot rotate to build the necessary pressure for the SCR (Selective Catalytic Reduction) system. This is often caused by crystallized DEF, frozen fluid in cold climates, internal mechanical failure of the pump, or a wiring issue preventing the motor from operating.

• T6 series
• T7 series
• T7.170
• T7.200
• T7.210
• T8 series
• T9 series
• TS6 series
• CX series combines
• FR forage harvesters
• Wheel loaders
• Crawler dozers

1. 1

   Check for other SCR/DEF fault codes (such as open circuits, temperature sensor faults, or voltage issues). If present, diagnose those first.

2. 2

   Inspect for freezing or crystallization. DEF freezes at 12°F (-11°C). Ensure the tank heater is working and that the pump is not simply blocked by frozen or heavily crystallized DEF fluid.

3. 3

   Inspect the wiring harness and the electrical connector at the DEF pump for corrosion, pushed-out pins, or chafing that could cause an open load or short circuit.

4. 4

   Use the New Holland E.A.S.Y. (Electronic Service Tool) to command the DEF pump to run. Monitor the pump speed and pressure build-up. If the pump receives the command and voltage but fails to spin or build pressure, the pump motor is internally blocked or failed.

1. 1

   Preparation

   Turn off the machine, disconnect the battery, and ensure the exhaust system has cooled down. Clean the area around the DEF pump to prevent dirt from entering the SCR system.

2. 2

   Disconnect Lines

   Carefully disconnect the DEF suction, pressure, and backflow lines from the supply module. Note: DEF is corrosive; clean up any spills immediately with warm water.

3. 3

   Disconnect Electricals

   Unplug the main wiring harness connector from the DEF pump.

4. 4

   Remove the Pump

   Unbolt the DEF pump/dosing module from its mounting bracket on the chassis or tank assembly.

5. 5

   Install the New Pump

   Mount the replacement DEF pump and secure the bolts. Reconnect the DEF fluid lines (ensure they click/lock into place) and the electrical connector.

6. 6

   Programming/Calibration

   The new DEF pump (Denoxtronic supply module) must be programmed and calibrated to the vehicle's DCU using the New Holland E.A.S.Y. diagnostic software.

7. 7

   Verification

   Clear the DCU 19155 / P208A fault code. Run the engine and use the diagnostic tool to perform a DEF system leak test and verify that the pump builds pressure successfully.