Case IH 19104 – DCU or EDC: Short Circuit to Ground of DEF/AdBlue Supply Module Heater Actuator powerstage

The control module has detected a short circuit to ground in the electrical circuit responsible for powering the heater inside the DEF Supply Module. The module disables the circuit to prevent damage, triggering this fault and potentially putting the engine into a derate (limp) mode.

• Tier 4b
• 5130
• 6130
• 7130
• 7230
• 8230
• 9230
• Maxxum 110
• Maxxum 115
• Maxxum 125
• Maxxum 140
• Magnum
• Steiger
• Farmlift 632
• Farmlift 635
• N-Series Loader Backhoes
• SR/SV/TR/TV series skid steers and compact track loaders
• M-Series dozers

1. 1

   Inspect the wiring harness running from the DCU/EDC to the DEF Supply Module for chafed, melted, or pinched wires touching the chassis.

2. 2

   Disconnect the electrical connector at the DEF Supply Module and use a multimeter to check the power supply pins on the harness side for continuity to ground.

3. 3

   Test the internal resistance of the heater pins on the DEF Supply Module to check if the internal heating element is shorted directly to the module's ground.

4. 4

   Check the connectors at both the DEF pump and the DCU for water intrusion, corrosion, or bent pins that could bridge the power and ground circuits.

1. 1

   Disconnect Power

   Turn off the ignition key and disconnect the machine's battery to prevent electrical spikes.

2. 2

   Repair Wiring

   If the diagnostic tests revealed a short in the harness, locate the damaged section (often where the harness routes against the frame) and splice/repair the wire using weather-sealed connectors.

3. 3

   Replace the DEF Supply Module

   If internally shorted, relieve any residual pressure in the DEF lines. Disconnect the electrical harness and the DEF fluid lines from the supply module. Unbolt the module from its mounting bracket and remove it. Install the new DEF Supply Module and reconnect the fluid lines and electrical connector.

4. 4

   System Reset and Testing

   Reconnect the battery. Using a dealer-level diagnostic tool (such as the CNH E.A.S.Y. tool or Jaltest), clear the fault codes.

5. 5

   Run a System Test

   Initiate a UDST (Urea Dosing System Test) via the diagnostic tool to command the pump and heater on, verifying that the short circuit code does not return and the system pressurizes correctly.