Case IH 19104 (F-519294-04) - ECU – Engine Control Unit (ECU) or DEF/AdBlue Dosing Control Unit (DCU): 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 powering the DEF supply module's internal heater. A short to ground means the electrical current is bypassing the heater element and going directly to the chassis, which typically blows a fuse, disables the heater, and will eventually lead to an engine derate due to SCR (Selective Catalytic Reduction) system failure.

• VESTRUM CVX
• Magnum (180 through 370)
• Steiger (350 through 600)
• Puma (130 through 215)
• Maxxum (110 through 140)
• Farmall series
• Axial-Flow 5130
• Axial-Flow 6130
• Axial-Flow 7130
• Axial-Flow 7230
• Axial-Flow 8230
• Axial-Flow 9230
• Patriot 4430
• Titan series
• Farmlift series

1. 1

   Inspect the Wiring Harness: Trace the wiring harness from the DEF supply module back to the ECU. Look for chafing, rubbing against the frame, or melted insulation that would cause the power wire to short against the grounded chassis.

2. 2

   Check Connectors: Disconnect the plug at the DEF supply module. Inspect for water ingress, DEF fluid intrusion (which is highly corrosive and causes shorts), or bent pins.

3. 3

   Test the Heater Element: Using a multimeter, measure the resistance across the heater pins on the supply module itself. If the resistance reads zero (continuity to the module casing/ground), the internal heater is shorted, and the module must be replaced.

4. 4

   Check Fuses/Relays: A short to ground almost always blows the circuit's protective fuse. Check the power distribution box for blown DEF heater fuses. If a fuse is blown, do not simply replace it without finding the short, or it will blow again.

1. 1

   Disconnect Power

   Disconnect the negative battery cable to prevent electrical spikes during the repair.

2. 2

   Locate the Module

   Locate the DEF supply module, which is typically mounted on the frame rail near the DEF tank.

3. 3

   Clean the Area

   Thoroughly clean the area around the module. DEF systems are highly sensitive to dirt and contamination.

4. 4

   Disconnect Lines & Wiring

   Disconnect the electrical harness. Depressurize the system if necessary, then disconnect the DEF suction, pressure, and backflow lines. Note: DEF is corrosive to metals and wiring; clean up any spills immediately with warm water.

5. 5

   Remove the Module

   Unbolt the supply module from its mounting bracket.

6. 6

   Install the New Module

   Mount the replacement DEF supply module and tighten the bolts to OEM specifications.

7. 7

   Reconnect

   Reconnect the DEF lines (ensure the quick-connect fittings "click" into place) and plug in the electrical connector.

8. 8

   Clear Codes and Prime

   Reconnect the battery. Use a diagnostic scan tool (such as the CNH EST) to clear the 19104 fault code. Run a DEF system leak test or dosing prime test via the software to purge air from the lines and verify the heater circuit is functioning without throwing a code.