Case IH 19103 – Engine Control Unit (ECU) or Dosing Control Unit (DCU): Short Circuit to Battery of DEF/AdBlue Supply Module Heater Actuator powerstage

In Tier 4 Final Selective Catalytic Reduction (SCR) systems, Diesel Exhaust Fluid (DEF) is prone to freezing at temperatures below 12°F (-11°C). To prevent this, the DEF Supply Module (also known as the DEF pump or dosing module) is equipped with an integrated heater. This fault code indicates that the control module has detected a short circuit to battery voltage (+) on the electrical circuit that powers and controls this specific heater.

• Tier 4b
• Magnum 180
• Magnum 190
• Magnum 210
• Magnum 225
• Magnum 235
• Magnum 260
• Magnum 290
• Magnum 340
• Magnum 370
• Maxxum 110
• Maxxum 115
• Maxxum 120
• Maxxum 125
• Maxxum 130
• Maxxum 140
• Puma 130
• Puma 145
• Puma 160
• Puma 170
• Puma 185
• Puma 200
• Puma 215
• Steiger 350
• Steiger 400
• Steiger 450
• Steiger 500
• Steiger 550
• Steiger 600
• Axial-Flow 5130
• Axial-Flow 6130
• Axial-Flow 7130
• Axial-Flow 7230
• Axial-Flow 8230
• Axial-Flow 9230
• Axial-Flow 5140
• Axial-Flow 6140
• Axial-Flow 7140
• Axial-Flow 7240
• Axial-Flow 8240
• Axial-Flow 9240
• Patriot 4430
• Titan 3030
• Titan 3530
• Titan 4030
• Titan 4530
• Farmlift 632
• Farmlift 635
• Farmlift 735
• Farmlift 742
• Farmlift 935

1. 1

   Reboot and Verify: Turn off the ignition switch until communication with the diagnostic scan tool is discontinued. Turn the ignition back on without starting the engine and observe if the DTC returns immediately (indicating a hard electrical fault).

2. 2

   Visual Inspection: Inspect the wiring harness leading to the DEF Supply Module. Look for chafing, melted insulation, or areas where the wire might be shorting directly to a 12V/24V power source.

3. 3

   Connector Check: Disconnect the electrical connector at the DEF Supply Module. Check for water intrusion, ice accumulation, or corrosion, which can bridge pins and cause a short circuit. Use a test pin to check for terminal drag (spread terminals).

4. 4

   Circuit Testing: With the module disconnected, use a multimeter to check the heater control circuit wires for continuity and verify if the short to battery voltage is present on the harness side.

5. 5

   Isolate the Component: If the harness tests good (no short to battery found in the wiring), the short circuit is internal to the DEF Supply Module's heater powerstage, meaning the module itself has failed and requires replacement.

1. 1

   Turn off the ignition switch and wait for the ECU to fully power down and save data. Disconnect the machine's battery.

   Ensure the system is fully powered down before beginning work.

2. 2

   Locate the DEF Supply Module.

   Typically mounted on a bracket near the DEF tank.

3. 3

   Thoroughly clean the area around the module.

   Prevents dirt from contaminating the SCR system.

4. 4

   Disconnect the electrical harness connector from the module.

   Remove the electrical connection to the DEF Supply Module.

5. 5

   Carefully disconnect the DEF fluid lines and the coolant/heater lines.

   Disconnect suction, pressure, and backflow lines. Be prepared to catch minor fluid spills.

6. 6

   Unbolt the DEF Supply Module from its mounting bracket.

   Remove the faulty module from the machine.

7. 7

   Install the new DEF Supply Module and secure it to the bracket.

   Mount the replacement module.

8. 8

   Reconnect all DEF lines, coolant lines, and the electrical connector.

   Ensure the DEF fluid in the tank is clean and uncontaminated to protect the new pump.

9. 9

   Reconnect the battery, turn on the ignition, and use a diagnostic scan tool to clear fault code 19103.

   Restore power and clear the fault code from the system.

10. 10

    Run the engine and command a system test.

    Verify the heater circuit operates correctly and check for any fluid leaks.