Case IH 19111 (DTC 723A) - ECU – DCU (Dosing Control Unit) / Engine ECU (ECM): DEF/AdBlue supply module pump motor short circuit to ground failure.

The system has detected that the control signal or power circuit for the DEF (Diesel Exhaust Fluid) pump motor is shorted to ground. This means the voltage is dropping to zero unexpectedly, which prevents the pump from building the necessary DEF pressure (typically up to 9 bar). This failure will trigger an SCR (Selective Catalytic Reduction) system malfunction, leading to an engine power loss or derate.

• MAXXUM T4E
• 240 Series Axial-Flow (7240, 8240, 9240)
• 130/140/150/160 Series
• Steiger (350 to 620)
• Magnum (180 to 380)
• Puma (130 to 240)
• Maxxum (110 to 150)
• Farmall series
• Patriot (4430, 4440)
• Titan Floaters

1. 1

   Battery & Voltage Test: Check the battery with a load tester. A failing battery that drops voltage significantly under load can cause the CAN bus to drop out momentarily, triggering false DEF pump short-circuit codes.

2. 2

   Wiring Harness Inspection: Visually inspect the wiring harness running from the DCU to the DEF supply module. Look for chafed, rubbed, or pinched wires that could be grounding out against the machine's chassis.

3. 3

   Circuit Testing: Disconnect the DEF pump connector. Use a multimeter to check for continuity to ground on the pump's power supply pin on the harness side. If there is continuity, the harness is shorted and needs repair.

4. 4

   Internal Pump Motor Test: If the harness tests fine, check the pins on the DEF pump itself. The DC motor inside the pump is prone to mechanical wear (brushes, bearings, windings) which can cause an internal short circuit.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to prevent electrical spikes.

2. 2

   Repair Wiring (If Applicable)

   If a short was found in the harness during diagnostics, repair the damaged wire and secure it in a protective loom away from vibration points.

3. 3

   Replace the DEF Supply Module (If Applicable)

   If the pump motor is internally shorted, the entire DEF supply module must be replaced. Relieve any residual pressure in the DEF lines. Disconnect the electrical connector and the DEF fluid lines from the pump module. Unbolt the pump assembly from its mounting bracket (or drop the tank if it is a tank-mounted flange assembly). Install the new DEF supply module and reconnect the fluid lines and electrical harness.

4. 4

   Reassemble and Reconnect

   Reconnect the battery.

5. 5

   Clear Codes and Prime

   Connect the Case IH Electronic Service Tool (EST). Clear the stored 19111 / 723A fault codes.

6. 6

   System Test

   Run a DEF system leak test or dosing test via the diagnostic tool to prime the new pump, verify DEF pressure, and ensure no leaks are present.