Case IH DCU19307 – DCU: Urea Pressure Too High

The Dosing Control Unit (DCU) has detected that the urea (DEF) pressure has exceeded the predefined upper limit. This indicates a fault in the Selective Catalytic Reduction (SCR) system's fluid delivery or pressure regulation components, which can negatively impact the proper operation of the emissions control system.

• Magnum 235
• Magnum 250
• Magnum 260
• Magnum 280
• Magnum 290
• Magnum 310
• Magnum 315
• Magnum 340
• Magnum 370
• Magnum 380

1. 1

   Check for other active or stored fault codes related to the DEF system, pressure sensor electrical circuits, temperature sensors, or the DEF pump

2. 2

   Inspect DEF quality, as old or contaminated fluid can crystallize and cause blockages

3. 3

   Visually inspect the wiring harness and connectors for the DEF pressure sensor and pump module for damage, corrosion, moisture intrusion, or loose connections

4. 4

   Check all DEF lines for kinks, restrictions, or visible blockages from crystallized DEF

5. 5

   Analyze live data with a scan tool to monitor DEF pressure sensor readings with the key on/engine off and while the engine is running to ensure pressure is within the manufacturer's specified range; an abnormally high reading when not actively dosing may point to a sensor or pressure regulation issue

1. 1

   Address related fault codes

   Resolve any other active fault codes first, especially those related to sensor circuits or the DEF pump.

2. 2

   Repair wiring and connectors

   If damage or corrosion was found during inspection, repair or replace the affected sections of the wiring harness or connectors. Ensure all connections are clean and secure.

3. 3

   Clear line blockages

   If a blockage is suspected, carefully disconnect the DEF lines and use a recommended flushing procedure or low-pressure compressed air to clear crystallized DEF. Consult the service manual for specific warnings and procedures to avoid damaging components.

4. 4

   Test DEF pressure sensor

   If live data readings are implausible, test the sensor's output voltage or resistance according to the service manual specifications.

5. 5

   Replace DEF pressure sensor

   If the sensor tests faulty, replace it. Note that it may be integrated into the DEF pump module or in-line within the pressure hose.

6. 6

   Inspect and replace DEF pump module

   If the sensor and lines are in good condition, the pump's internal pressure-regulating mechanism may be malfunctioning. Replace the DEF pump module if necessary.

7. 7

   Clear codes and verify

   Clear the fault codes using a diagnostic tool and operate the tractor under normal conditions to allow the SCR system to run through its cycles and verify the fault does not return.