Case IH 19056 – DCU (Dosing Control Unit): UREA Temperature sensor in box (electrical) | signal low | P2044 Reagent -temperature sensor of pump module -short circuit low

The DEF (Diesel Exhaust Fluid / Urea) temperature sensor located inside the DEF pump module is reporting a short circuit to ground (signal voltage is too low, typically dropping below the 0.5V threshold).

• Tier 4a
• Magnum 235-340 Series 4
• Magnum 180-250
• Steiger 350-600
• Puma 150-200
• Maxxum
• Optum
• 5130-9230 series combines
• Patriot sprayers

1. 1

   Inspect the wiring harness and the electrical connector at the DEF pump module for corrosion, water intrusion, bent pins, or physical damage caused by road debris or rodents.

2. 2

   Check the wiring harness for a short to ground between the DCU and the DEF pump module.

3. 3

   Use a diagnostic scan tool (like the CNH Electronic Service Tool) to monitor the live voltage of the DEF temperature sensor. A healthy circuit should read between 0.5V and 4.5V. If it reads near 0V and the wiring is intact, the sensor itself has failed.

1. 1

   Preparation

   Turn off the machine and disconnect the battery to prevent electrical spikes. Clean the area around the DEF pump module thoroughly to ensure no dirt or contaminants enter the DEF lines during removal.

2. 2

   Disconnection

   Disconnect the main electrical harness connector from the DEF pump module.

3. 3

   Line Removal

   Carefully disconnect the DEF fluid lines and coolant lines (if applicable) from the pump. Have a clean catch pan ready, as some fluid will leak out.

4. 4

   Removal

   Unbolt the mounting hardware securing the DEF pump module to the chassis/bracket and remove the faulty unit.

5. 5

   Installation

   Mount the new DEF pump module and tighten the hardware. Reconnect the DEF lines, coolant lines, and the electrical harness.

6. 6

   Programming

   Reconnect the battery. Note: A new DEF module will likely need to be programmed/calibrated to the vehicle's ECU using the OEM diagnostic software (CNH EST) before it will function correctly.

7. 7

   Testing

   Clear the fault codes, run the machine, and check for leaks and proper DEF dosing operation.