New Holland NH 4125 – EHR (Electronic Hitch/Hydraulic Remote) controller or Arm Rest Module (ARU) / Auxiliary Remote Valve Controller: Remote No.2 potentiometer faulty

The electronic control system has detected that the electrical signal from the position sensor (potentiometer) on the #2 rear remote spool valve is out of range, missing, or implausible. The tractor's computer cannot determine the physical position of the spool valve.

• T6 Series
• T7 Series
• T8 Series
• T9 Series
• T6000 Series
• T7000 Series
• TM Series

1. 1

   Visual Inspection: Inspect the wiring harness and connectors going directly to the Rear Remote No. 2 valve block at the back of the tractor for open circuits, short circuits, or heavy corrosion.

2. 2

   Voltage Check: Verify that the supply voltage to the potentiometer is within the correct range (typically 5V reference from the controller).

3. 3

   Swap Test: Swap the electrical connector from Remote No. 2 with a known good remote valve (such as Remote No. 1 or No. 3). If the fault code changes to the new valve (e.g., NH 4111 for Remote No. 1), the sensor/valve is faulty. If the NH 4125 code persists, the issue is in the tractor's wiring harness or the EHR controller.

1. 1

   Depressurize

   Turn off the tractor, lower all implements, and relieve all hydraulic system pressure.

2. 2

   Locate the Valve

   Locate the Rear Remote No. 2 valve slice in the hydraulic stack at the rear of the tractor.

3. 3

   Disconnect

   Disconnect the electrical harness from the Remote No. 2 potentiometer/electronic control head.

4. 4

   Replace Component

   Unbolt and replace the faulty potentiometer. (Note: Depending on the exact valve manufacturer—e.g., Bosch Rexroth or Danfoss—the sensor may be serviced independently, or you may have to replace the entire electronic control head/actuator on top of the valve slice).

5. 5

   Reconnect

   Reconnect the wiring harness securely.

6. 6

   Clear Codes

   Turn the key ON and use the tractor's diagnostic H-menu or a dealer service tool to clear the inactive fault code.

7. 7

   Calibrate

   You must perform a hydraulic remote valve calibration procedure (usually accessed via the H-menu or diagnostic tool). This teaches the controller the new sensor's exact neutral, maximum extend, and maximum retract voltage limits.