Case IH 19047 – DCU (Dosing Control Unit): UREA pressure sensor in box (electrical) _signal high _P204D Reagent -pressure sensor -short circuit high

The system has detected that the signal voltage from the DEF (Urea) pressure sensor is exceeding the maximum expected threshold, indicating a short circuit to a high voltage source (such as battery voltage). The pressure sensor is located internally within the DEF Supply Module.

• Tier 4a
• Tier 4b
• Magnum (180 through 380)
• Steiger (350 through 620)
• Puma (130 through 240)
• Maxxum (110 through 140)
• Axial-Flow 5130
• Axial-Flow 6130
• Axial-Flow 7130
• Axial-Flow 7230
• Axial-Flow 8230
• Axial-Flow 9230
• Patriot 4430
• Titan series

1. 1

   Turn off the ignition switch (Key Off).

2. 2

   Inspect the wiring harness between the DCU and the DEF supply module for chafing, melting, or pinched wires that could cause a short to power.

3. 3

   Disconnect the electrical connectors at both the DCU and the DEF supply module. Inspect the pins for corrosion, bent terminals, or DEF fluid intrusion (which can cause electrical shorts).

4. 4

   Use a multimeter to test the pressure sensor signal circuit for a short to battery voltage. Verify that the 5V reference circuit and ground circuits are intact and not shorted to other wires.

5. 5

   Reconnect the harness, turn the key ON, and use a diagnostic scan tool to clear the DTC. If code 19047 / P204D immediately returns and the external wiring is good, the internal pressure sensor has failed.

1. 1

   Turn off the machine, disconnect the battery, and allow the DEF system to purge/depressurize.

2. 2

   Locate the DEF supply module (typically mounted near the DEF tank). Clean the surrounding area thoroughly to prevent dirt or debris from entering the DEF system.

3. 3

   Disconnect the main electrical harness connector from the module.

4. 4

   Carefully disconnect the DEF inlet, outlet, and backflow lines.

   Note: Be prepared with a clean catch pan, as residual DEF fluid will spill.

5. 5

   Unbolt the mounting hardware and remove the faulty DEF supply module.

6. 6

   Install the new DEF supply module and secure the mounting bolts.

7. 7

   Reconnect the DEF lines, ensuring the quick-connect fittings click securely into place.

8. 8

   Reconnect the electrical harness.

9. 9

   Reconnect the battery, turn the ignition ON, and use a diagnostic tool to clear the fault codes.

10. 10

    Run the engine and perform a DEF system leak test or dosing test.

    The system should build and maintain a urea fluid pressure of approximately 900 kPa (131 psi) without the code returning.