New Holland NH 4117 – Arm Rest Module (ARU) or EHR (Electronic Hydraulic Remote) Controller: Remote No.2 Switched to failsafe

The electronic controller has detected a critical error in the circuit or operation of the Rear Remote Valve #2 and has placed it into a failsafe mode to prevent unintended hydraulic movement, overheating, or deadheading the hydraulic pump.

• T-Series (T6, T7, T8, T9)
• TM Series (TM115, TM175, etc.)
• TG Series (TG285, etc.)
• TS Series
• TN Series

1. 1

   Check the diagnostic display for accompanying sub-codes (e.g., 4118, 4120, 4125) to determine if the issue is electrical or mechanical.

2. 2

   Inspect the wiring harness and connectors at the rear hydraulic remote block for corrosion, water ingress, or loose pins at Valve #2.

3. 3

   Check hydraulic oil temperature and level, as cold or thick oil (below 5°C / 41°F) can cause sluggish spool movement and trigger a failsafe.

4. 4

   Attempt a spool travel calibration via the tractor's onboard H-menu or the Electronic Service Tool (EST) to rule out minor mechanical stick or software drift.

1. 1

   Relieve Hydraulic Pressure

   Turn off the tractor and cycle the remote levers/buttons to relieve all residual hydraulic pressure.

2. 2

   Isolate the Fault

   If you suspect the armrest joystick/paddle potentiometer is faulty, swap the electrical connection with Remote No.1 or No.3. If the fault moves to the new remote, the armrest control is the issue. If the fault stays on Remote No.2, the issue is at the rear valve block.

3. 3

   Replace the Potentiometer

   If the diagnostic code points to a faulty potentiometer (Code 4125), remove the sensor cap on the rear of the remote valve slice and install a new potentiometer.

4. 4

   Clean or Rebuild the Valve Slice

   If the spool is physically sticking (Code 4120/4121): Unbolt the Remote No.2 slice from the rear hydraulic stack, disassemble the valve, clean the spool and bore thoroughly, and install a new O-ring and seal kit.

5. 5

   Replace the Valve Section

   If the internal driver is faulty (Code 4124) or the spool is scored, the entire Remote No.2 valve section must be replaced.

6. 6

   Recalibrate

   After replacing any sensors, seals, or the valve itself, you must perform an EHR valve calibration using the New Holland Electronic Service Tool (EST) or the tractor's diagnostic menu.