Case IH 4171 – DU Module: Rear EHR control No.1 - open circuit (DU module only)

An open circuit indicates that the control module is sending a signal to the No. 1 rear remote valve solenoid or receiving a signal from the No. 1 control pod/switch, but the electrical loop is broken. The module cannot detect continuity, which disables the function of the No. 1 rear remote.

• Maxxum
• Case IH Puma Series
• Case IH Magnum Series
• Case IH Steiger Series
• Case IH Farmall Series

1. 1

   Inspect the wiring harness routing from the cab down to the rear hydraulic valve stack for chafed wires, rodent damage, or pinched harnesses

2. 2

   Disconnect the electrical connector at the Rear EHR No. 1 control valve and check for water ingress, corrosion, or pushed-back pins

3. 3

   Measure the resistance across the pins of the EHR No. 1 valve solenoid coil using a multimeter (an infinite/OL reading indicates the coil is internally open)

4. 4

   Check the continuity of the wiring harness between the valve connector and the control module

5. 5

   Verify the EHR No. 1 control switch/pod in the cab armrest for a failed potentiometer or local wiring issues

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the battery to prevent electrical spikes.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a broken wire or corroded connector, repair the harness using an OEM-approved wiring repair kit or replace the damaged connector pigtail.

3. 3

   Replace Faulty Component

   If the valve solenoid is open, remove the retaining nut/screws on the No. 1 EHR valve and replace the solenoid coil (or the entire valve slice if the coil is not serviced separately). If the in-cab switch is faulty, remove the armrest trim and replace the EHR control pod.

4. 4

   Reconnect and Power Up

   Reconnect the battery and turn the key switch to the ON position.

5. 5

   Valve Renumbering / Calibration

   If a new valve or pilot head was installed, access the tractor's diagnostic menu (often the 'HH' or 'HK' menu on the instrument cluster), navigate to the Rear EHR options (e.g., menu H3), follow the prompt to renumber the valves, reconnect the valves in the correct order, and clear the stored 4171 fault code from the EEPROM.