Case IH 4181 – DU Module: Rear EHR control no.4 - open circuit (DU module only)

The control module has detected an open electrical circuit (a broken wire, disconnected plug, or burnt-out internal solenoid) on the circuit controlling the #4 rear hydraulic remote valve.

• Maxxum
• Puma Series
• Maxxum Series
• Steiger Series
• Magnum Series
• Farmall Series
• Optum Series

1. 1

   Inspect the EHR control valve wiring harness connecting the DU module to the rear remote valve block for obvious signs of chafing, rodent damage, or severed wires.

2. 2

   Disconnect the plug at the #4 rear remote valve and the DU module to check for pushed-out pins, corrosion, or moisture ingress.

3. 3

   Using a multimeter, test the signal and ground wires between the DU module and the #4 EHR valve for continuity.

4. 4

   Measure the resistance across the pins of the #4 EHR control valve solenoid. A reading of infinite resistance (OL) indicates the internal solenoid is burnt out.

1. 1

   Depressurize and Power Down

   Turn off the tractor, relieve all hydraulic system pressure, and disconnect the battery to protect the CAN BUS system.

2. 2

   Access the Components

   Locate the rear remote valve stack at the back of the tractor and identify the #4 valve section.

3. 3

   Repair/Replace Wiring

   If the diagnostic tests revealed a broken wire, repair it using weather-sealed connectors. If the harness is heavily damaged, replace the entire EHR control valve wiring harness.

4. 4

   Replace the Valve (If Faulty)

   If the open circuit is internal to the valve solenoid, disconnect the hydraulic lines and the electrical connector to the #4 valve. Unbolt the #4 section from the remote valve stack and install the replacement EHR valve section.

5. 5

   Reassembly

   Reconnect all hydraulic lines, electrical plugs, and the battery.

6. 6

   Clear and Calibrate

   Start the tractor. Use the onboard instrument cluster or an electronic service tool to clear the 4181 fault code. You must perform a hydraulic remote valve calibration procedure so the DU module recognizes the new valve/repaired circuit.