Case IH F-5435-04 - ECU – ECU: DEF/AdBlue supply module pump motor short circuit to ground failure

The system has detected a short circuit to ground in the control circuit for the DC motor inside the Diesel Exhaust Fluid (DEF) supply module. Because the motor is shorted, the pump cannot operate, resulting in no DEF flow, loss of system prime, and an eventual engine power derate or full system shutdown.

• MAGNUM AFS Connect
• 240 Series Combines (7240, 8240, 9240)
• 130 and 230 Series Combines (5130, 6130, 7130, 7230)
• Steiger (350, 400, 450, 500, 550, 600)
• Magnum (180 through 370)
• Puma
• Maxxum
• Farmall
• Patriot (4430)
• Titan floaters

1. 1

   Battery Load Test: Test the battery with a dedicated load tester to rule out voltage dips causing false pump faults.

2. 2

   Wiring Harness Inspection: Inspect the wiring harness between the ECU/DCU and the DEF supply module for chafing, rubbing, or pinched wires.

3. 3

   Circuit Isolation: Disconnect the electrical connector at the DEF pump and use a multimeter to check for continuity to ground on the motor control circuit.

1. 1

   Preparation

   Disconnect the machine's battery. Depending on the machine's specific architecture, the pump may be integrated into the top flange of the DEF tank or mounted remotely on the frame rail.

2. 2

   Access

   If tank-mounted, you may need to drop the DEF tank or access the top flange assembly.

3. 3

   Removal

   Thoroughly clean the area around the pump to prevent dirt from entering the DEF system. Disconnect the electrical connectors and the heated DEF fluid lines from the supply module. Unbolt the module and remove it.

4. 4

   Installation

   Install the new DEF supply module. Reconnect the fluid lines and electrical connectors securely.

5. 5

   Programming

   A new DEF dosing module must be programmed/calibrated to the vehicle's ECU using the Case IH Electronic Service Tool (EST) after replacement.

6. 6

   Validation

   Clear the fault codes. Run the machine to operating temperature or initiate a forced DEF system test to ensure the pump primes, builds pressure (up to 9 bar/130 psi), and the code does not return.