Case IH F-4376-04 - ECU – DCU (Dosing Control Unit) or Engine ECU: DEF/AdBlue reverting valve driver circuit short to ground failure

The reverting valve (4-2 way valve or reductant purge control valve) cycles to reverse the flow of the DEF pump when the engine is shut down, purging the lines of DEF to prevent freezing. A short to ground indicates the control module has detected that the electrical circuit supplying power or ground to this valve is shorted directly to the chassis ground, causing excessive current draw or a complete loss of valve control.

• MAGNUM AFS Connect
• 240 Series Axial-Flow (7240, 8240, 9240)
• 130 Series Axial-Flow
• 230 Series Axial-Flow
• Steiger (350-600)
• Magnum (180-370)
• Puma
• Maxxum
• Farmall
• Farmlift
• Patriot

1. 1

   Key Off: Turn off the ignition switch and wait for the aftertreatment system to complete its purge cycle and power down completely.

2. 2

   Harness Inspection: Inspect the wiring harness running between the DCU and the DEF Supply Module. Look for chafed insulation, pinched wires, or bare copper touching the machine's metal frame.

3. 3

   Connector Check: Disconnect the electrical connector at the DEF Supply Module. Inspect the pins for corrosion, water intrusion, or dried white urea crust.

4. 4

   Circuit Testing: Use a multimeter to test the reverting valve control circuit for continuity to ground. If the wire is grounded while disconnected from the module, the harness is at fault.

5. 5

   Coil Resistance: Test the reverting valve pins on the module itself. If the internal coil of the valve is shorted out, the module must be replaced.

1. 1

   Disconnect battery

   Disconnect the machine's battery to prevent electrical spikes.

2. 2

   Locate DEF Supply Module

   Locate the DEF Supply Module (usually mounted on a bracket near the DEF tank).

3. 3

   Clean module area

   Thoroughly clean the outside of the module and the surrounding area to prevent dirt or dried urea crystals from contaminating the open lines.

4. 4

   Disconnect electrical harness

   Disconnect the electrical harness connector.

5. 5

   Disconnect fluid lines

   Carefully disconnect the DEF suction, pressure, and return lines. Note: Be prepared to catch spilled DEF fluid. If the module is equipped with engine coolant lines for heating, pinch off and disconnect those as well.

6. 6

   Remove supply module

   Unbolt the supply module from its mounting bracket and remove it.

7. 7

   Install new module

   Install the new DEF Supply Module and torque the mounting bolts to OEM spec.

8. 8

   Reconnect lines and harness

   Reconnect all fluid lines, ensuring the fittings click securely into place. Reconnect the electrical harness.

9. 9

   Clear fault codes

   Reconnect the battery and turn the ignition ON. Use a diagnostic scan tool to clear the F-4376-04 / 19083 / 19182 fault codes.

10. 10

    Test system

    Start the engine and use the scan tool to command a DEF system leak test or prime test to ensure the system builds pressure (approx. 9.0 bar / 130.5 psi) and the reverting valve operates correctly upon shutdown.