Case IH 19073 – DCU (Dosing Control Unit): Voltage supply 2 - tube heaters (UB2) electrical | Short to bat at UB2 with Key 15 off

The system has detected a high-voltage short circuit (short to battery) in the power supply circuit for the internal tubular heaters (specifically the DEF/reagent suction tube heating circuit) while the ignition key (Key 15) is turned off.

• Tier 4a
• Tier 4b
• Magnum 180
• Magnum 190
• Magnum 210
• Magnum 225
• Magnum 235
• Magnum 260
• Magnum 290
• Magnum 315
• Magnum 340
• Magnum 370
• Steiger 350
• Steiger 400
• Steiger 450
• Steiger 500
• Steiger 550
• Steiger 600
• Puma 130
• Puma 145
• Puma 160
• Puma 170
• Puma 185
• Puma 200
• Puma 215
• Maxxum 110
• Maxxum 115
• Maxxum 120
• Maxxum 125
• Maxxum 130
• Maxxum 140
• Axial-Flow Combine 5130
• Axial-Flow Combine 6130
• Axial-Flow Combine 7130
• Axial-Flow Combine 7230
• Axial-Flow Combine 8230
• Axial-Flow Combine 9230
• Patriot Sprayer 4430

1. 1

   Inspect external wiring harnesses and connectors leading to the DEF Supply Module (DCU) for corrosion, moisture, or physical damage

2. 2

   Ensure that the DEF suction pipelines are in working order and not physically damaged or leaking

3. 3

   Clear the fault code using a diagnostic tool and cycle the ignition to see if it immediately reoccurs, indicating a hard internal failure

1. 1

   Turn off the ignition switch and disconnect the battery

   Ensure no power is running to the DCU.

2. 2

   Disconnect the electrical harnesses and DEF fluid lines from the DEF Supply Module

   Clean the surrounding area of any dried white urea crust or dust before removing lines to prevent contamination of the SCR system.

3. 3

   Unbolt and remove the faulty DEF Supply Module

   Remove it from its mounting bracket.

4. 4

   Install the replacement DEF Supply Module

   Reconnect the fluid lines and electrical harnesses.

5. 5

   Perform software configuration

   Use the manufacturer's diagnostic tool (e.g., Case IH EST) to configure the new module to the machine's CAN-bus system.

6. 6

   Clear the fault codes and verify repair

   Clear the P20C4 / 19073 fault codes and run the machine to verify the SCR system builds pressure and the code does not return.