Case IH 4178 – DU Module: Rear EHR control no.3 - open circuit (DU module only)

The system has detected an "open circuit" in the electrical circuit responsible for controlling the #3 Rear Electro-Hydraulic Remote (EHR) valve. This means electrical continuity has been lost, preventing the controller from operating the #3 remote valve. The interruption is typically caused by a disconnected plug, a broken wire in the harness, or an internally failed (open) solenoid coil on the valve itself.

• Maxxum
• Steiger
• Quadtrac
• Puma
• Magnum
• Optum

1. 1

   Locate the #3 rear remote valve on the rear hydraulic valve stack.

2. 2

   Check the electrical connectors plugging into the #3 remote valve solenoids to ensure they are fully seated, locked, and free of dirt, debris, or corrosion.

3. 3

   Trace the wiring harness from the rear remotes back toward the cab, paying special attention to areas secured with 'P' clamps or passing through articulation joints.

4. 4

   Disconnect the harness at the #3 valve and use a multimeter to measure the resistance across the solenoid coil pins to check for an internally open coil.

5. 5

   If the coil tests good, check the harness for continuity back to the DU module to isolate a broken wire.

1. 1

   Relieve Pressure & Power Down

   Turn off the tractor, lower all implements, and relieve hydraulic pressure in the system. Turn off the battery disconnect switch.

2. 2

   Inspect and Clean

   Disconnect the electrical connectors at the #3 EHR valve. Spray the contacts with electrical contact cleaner and inspect for pushed-out pins or moisture intrusion.

3. 3

   Test the Solenoids

   Test the top and bottom solenoids of the #3 valve for continuity. If a solenoid is open, replace the faulty solenoid coil or the affected EHR valve section.

4. 4

   Repair the Harness

   If the solenoids are functional, trace the wiring harness to locate the break. Carefully open the wire loom at suspected pinch points or articulation joints.

5. 5

   Splice or Replace

   Repair the broken wire using weather-sealed (heat-shrink) butt connectors. If the harness is severely chafed or degraded, replace the entire EHR control valve wire harness section.

6. 6

   Reassemble and Clear Codes

   Reconnect all plugs, restore battery power, and start the tractor. Clear the inactive fault codes from the DU module and actuate the #3 remote to verify the repair.