Case IH 19108 (F-5435-03) - ECU – Engine Control Unit (ECU): DEF/AdBlue supply module pump motor short circuit to battery failure

The engine's control system has detected that the electrical circuit controlling the DEF (Diesel Exhaust Fluid) pump motor is shorted to a high voltage source (battery voltage).

• VESTRUM CVX
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• Magnum
• Steiger
• Puma
• Maxxum
• Farmall
• Patriot
• Titan
• Farmlift
• A9900

1. 1

   Check battery and system voltage during engine cranking to rule out low voltage causing cascading CAN bus and DEF system faults.

2. 2

   Inspect the wiring harness and connectors at the DEF supply module for damaged pins, loose machine grounds, or water/debris inside the terminals.

3. 3

   Test the DEF pump motor control signal circuit for a short to a high source (battery voltage).

4. 4

   Turn on the ignition without starting the engine, use a diagnostic scan tool to clear the code, and verify if the short circuit fault immediately returns.

1. 1

   Preparation

   Stop the machine, turn off the ignition, and allow the engine and exhaust system to cool completely. Disconnect the battery.

2. 2

   Clean the Area

   Ensure the area surrounding the DEF supply module is completely clean of dust and dried, white urea crust. If you need to flush the external housing face, use only clean distilled water to safeguard the internal high-pressure fluid loops.

3. 3

   Removal

   Disconnect the electrical harness connectors and the DEF fluid lines from the supply module. Unbolt the module from its mounting bracket.

4. 4

   Filter Replacement

   If you are only replacing the internal filter element, use the specialized extraction tool included in the OEM filter kit to carefully pull the old filter. Do not scratch the inner walls of the pump housing reservoir.

5. 5

   Installation

   Mount the new DEF supply module. Reconnect the fluid lines and the electrical harness.

6. 6

   System Reset

   Reconnect the battery. Turn the ignition switch ON (without starting the engine) and use the diagnostic scan tool to clear the fault codes (including 19108 and any related P20C9 codes).