New Holland DCU 19370 – DCU (Dosing Control Unit): UREA pressure too low (in ‘commissioning’ status) | Pump motor error during commissioning

During the system startup or 'commissioning' phase, the DEF (Diesel Exhaust Fluid / Urea) pump is failing to build the required pressure. The system attempts to prime the lines, but the pressure remains too low, either because the pump motor is physically not delivering fluid, there is an air leak in the suction line, or the pump motor is experiencing an electrical/mechanical error.

• T6 series (T6.120 to T6.175)
• T7 series (T7.170 to T7.260)
• T8 series
• T9 series
• CR series (CR6090 to CR9.90)
• CX series (CX8070, CX8090)
• LM series (LM6.32 to LM9.35)
• W190B
• 821F/921F wheel loaders

1. 1

   Verify DEF/Urea level in the tank manually (do not rely solely on the gauge) and inspect for frozen fluid, crystallization, or debris.

2. 2

   Turn the key on and listen to hear if the DEF pump motor is audibly running during the priming phase.

3. 3

   Inspect the DEF feeding/suction lines for leaks, cracks, or breaks. Specifically check the O-rings inside the line connectors for air leaks.

4. 4

   Inspect the wiring harness and connector pins at the DEF Supply Module for damaged wires, loose machine grounds, or water/debris inside the connector terminals.

5. 5

   Use a diagnostic tester to manually start the pump and open the ventilation valve by 50%. Check if UREA pressure reaches 600 hPa, then close the valve and verify if pressure spikes to approximately 3000 hPa within 2 minutes.

1. 1

   Safety shutdown

   Stop the engine, turn off all power, and allow the exhaust and aftertreatment system to cool completely before servicing.

2. 2

   Clear blockages

   If diagnostic tests point to a blockage, replace the DEF suction filter and inspect the return line fitting (which contains a return orifice that can become blocked).

3. 3

   Replace the Supply Module

   If the wiring is sound, there are no air leaks in the suction line, and the pump motor is either dead or internally failing to build pressure, replace the DEF Supply Module (Pump/DCU).

4. 4

   Software calibration

   Install the new DEF Supply Module. Use the New Holland Electronic Service Tool (EST) to install software and flash/program the new integrated DCU to the vehicle's main ECU.

5. 5

   System prime

   Run a 'Pressure Build Up Operation' or system prime via the diagnostic tool to verify the new pump successfully commissions and clears the P208B / 19370 code.