Case IH 19058 – DCU (Dosing Control Unit): UREA Temperature sensor in box (electrical) – signal low

The temperature sensor located internally within the DEF pump module is sending a voltage signal that is too low or outside the expected operating parameters, indicating an internal short circuit to ground or a complete failure of the sensor.

• Tier 4a
• Magnum (180-380)
• Steiger (350-620)
• Puma (130-240)
• Maxxum
• Optum
• Farmall
• Axial-Flow (5130, 6130, 7130, 7230, 8230, 9230, 7240, 8240, 9240)
• Patriot (2250, 3240, 3340, 4430)
• Titan Floaters
• Farmlift Telehandlers
• WD-series Windrowers

1. 1

   Inspect the wiring harness connecting the DCU to the DEF pump module for chafing, breaks, or pinched wires that could cause a short to ground.

2. 2

   Disconnect the electrical connector at the DEF pump module and check for bent pins, corrosion, or moisture/DEF fluid intrusion.

3. 3

   Connect the CNH Electronic Service Tool (EST) laptop and monitor live data for the DEF pump module temperature. If the reading shows an extreme default value (e.g., -40°C) and external wiring tests good, the internal sensor has failed.

1. 1

   Turn off machine

   Turn off the machine, remove the key, and disconnect the battery.

2. 2

   Locate DEF pump module

   Locate the DEF pump module (typically mounted on the frame rail near the DEF tank).

3. 3

   Clean module exterior

   Thoroughly clean the exterior of the module and the surrounding area to prevent dirt or debris from entering the DEF lines during removal.

4. 4

   Disconnect electrical harness

   Disconnect the main electrical harness connector from the module.

5. 5

   Disconnect and cap DEF lines

   Carefully disconnect the DEF suction, backflow, and pressure lines. Cap the lines immediately to prevent contamination and fluid loss.

6. 6

   Remove faulty module

   Remove the mounting bolts securing the pump module to the bracket and remove the faulty unit.

7. 7

   Install new module

   Install the new DEF pump module and tighten the mounting bolts.

8. 8

   Reconnect DEF lines

   Remove the caps and reconnect the DEF fluid lines, ensuring they click securely into place.

9. 9

   Reconnect electrical harness

   Reconnect the electrical harness.

10. 10

    Reconnect battery

    Reconnect the battery.

11. 11

    Program and initialize module

    Connect the CNH Electronic Service Tool (EST). The new DEF supply module must be programmed and initialized to the vehicle's DCU for the system to recognize it and clear the engine derate.

12. 12

    Clear codes and test

    Clear the fault codes and run a DEF system dosing test via the EST to verify proper operation, pressure building, and to check for leaks.