Case IH 19083 (DTC 7D5A) - ECU – DCU (Dosing Control Unit): DEF/AdBlue reverting valve driver circuit short to ground failure

The system has detected a short circuit to ground on the voltage supply circuit (UB3) that powers the coolant control valve and the reverting valve (reductant purge control valve).

• MAXXUM T4E
• Magnum 180-370
• Magnum Series 4 235-340
• Steiger 350-600
• Maxxum 110-140
• Puma 130-215
• Farmall 35C
• Farmall 40
• Farmall 45
• Farmall 50
• Farmall 95A
• Farmall 100C
• Farmall 110C
• Axial-Flow 7240
• Axial-Flow 8240
• Axial-Flow 9240
• Axial-Flow 5130
• Axial-Flow 6130
• Axial-Flow 7130
• Axial-Flow 7230
• Axial-Flow 8230
• Patriot 3030
• Patriot 3530
• Patriot 4030
• Patriot 4430
• Patriot 4530
• Titan 3030
• Titan 3530
• Titan 4030
• Titan 4430
• Titan 4530
• Farmlift 632
• Farmlift 635
• Farmlift 735
• Farmlift 742
• Farmlift 935

1. 1

   Inspect the wiring circuit between the DCU/Supply Module and the reverting valve/coolant control valve for any chafing, bare wires, or physical damage that would cause a short to ground.

2. 2

   Verify that all electrical connectors on the NOx neutralization/DEF supply module are securely connected and that no pins are corroded, bent, or damaged.

3. 3

   Ensure the DEF/AdBlue plumbing lines are in working condition and free of restrictions, as blockages can impact the module's ability to purge.

4. 4

   Use a diagnostic scan tool to attempt to clear the code. If the code immediately returns or cannot be cleared, the fault is a hard failure likely internal to the module.

1. 1

   Turn off ignition and disconnect battery

   Turn off the machine's ignition and disconnect the battery to ensure safety while working on the electrical and emissions systems.

2. 2

   Locate DEF/AdBlue Supply Module

   Locate the DEF/AdBlue Supply Module (pump module) on the machine.

3. 3

   Inspect external wiring harness

   Carefully inspect the external wiring harness (specifically the UB3 voltage supply circuit) leading to the module. If a short to ground is found in the external wiring, repair the wire, reconnect, and test the system.

4. 4

   Determine if short is internal

   If the external wiring and connectors are in good condition, the short circuit is internal to the reverting valve actuator or the supply module's circuitry.

5. 5

   Replace DEF/AdBlue Supply Module

   Because the reverting valve is an internal component of the DEF/AdBlue Supply Module, the valve itself cannot be serviced separately. You must replace the entire DEF/AdBlue Supply Module (NOx neutralization unit).

6. 6

   Disconnect fluid lines and connectors

   Disconnect the DEF fluid lines and electrical connectors from the Supply Module. Be prepared to catch any residual DEF fluid.

7. 7

   Remove faulty module

   Unbolt the mounting hardware and remove the faulty module.

8. 8

   Install new module

   Install the new DEF Supply Module, reattach the mounting hardware, and securely reconnect all fluid lines and electrical connectors.

9. 9

   Clear code and retest

   Reconnect the battery, turn on the ignition, and use a diagnostic scan tool to clear fault code 19083 (7D5A). Run the engine to verify the system pressurizes and that the code does not return.