Case IH 19047 (F-4334-03) – DCU (Dosing Control Unit): DEF/AdBlue supply module pump motor pressure sensor voltage is higher than expected

The control module is receiving a voltage signal from the DEF pressure sensor that exceeds the maximum allowable limit, meaning the sensor's signal circuit is shorted to a high-voltage source (such as a 5V reference or 12V battery power), or the sensor has failed internally.

• VESTRUM CVX
• Magnum series (180-370, 235-340 Series 4)
• Steiger series (350-600)
• Maxxum series (110-140)
• Puma series (130-215)
• 5130
• 6130
• 7130
• 7230
• 8230
• 9230
• Patriot (4430)
• Titan series
• Farmlift series

1. 1

   Inspect the wiring harness running from the DCU to the DEF supply module for heat damage, chafing against the frame, or pinched wires that could cause a short to power.

2. 2

   Disconnect the DEF supply module electrical connector and check for bent pins, corrosion, or DEF fluid intrusion (white crystallization inside the plug).

3. 3

   Connect a diagnostic scan tool and monitor the live voltage of the DEF pressure sensor, then unplug the connector at the DEF supply module. If voltage drops to zero, the short is internal to the module. If voltage remains high, the short is in the machine's wiring harness.

1. 1

   Preparation

   Turn off the machine, disconnect the battery, and ensure the exhaust and DEF systems have cooled. Thoroughly clean the area around the DEF pump to prevent dirt or crystallized urea from entering the open fluid lines.

2. 2

   Relieve Pressure

   If the system hasn't auto-purged, carefully crack the lines to relieve any residual pressure.

3. 3

   Disconnect Lines

   Disconnect the DEF suction, pressure, and backflow lines from the supply module. Cap the lines immediately to prevent contamination.

4. 4

   Disconnect Wiring

   Unplug the main electrical harness connector from the module.

5. 5

   Removal

   Unbolt the DEF supply module from its mounting bracket (or the DEF tank flange, depending on the specific machine's architecture) and remove the unit.

6. 6

   Installation

   Mount the new DEF supply module and torque the mounting bolts to OEM spec.

7. 7

   Reconnection

   Remove the caps and reconnect the DEF fluid lines (ensuring the quick-connects click securely into place) and plug in the electrical connector.

8. 8

   System Prime and Clear Codes

   Reconnect the battery. Use a diagnostic scan tool to clear the 19047 (F-4334-03) fault code. Run a DEF system prime/doser test via the scan tool to bleed air from the lines, build pressure, and verify there are no leaks before returning the machine to service.