New Holland NH 4119 – Arm Rest Module (ARU) or ATC (Auxiliary Tractor Control / Alta Implement): Remote No.2 Over voltage

The control module is receiving a voltage signal from the Rear Remote No. 2 hydraulic valve circuit (specifically the spool position potentiometer or transducer) that exceeds the expected maximum threshold. This usually indicates a short to power in the wiring harness or an internal failure of the potentiometer itself.

• New Holland T7 Series (T7.220, T7.235, T7.250, T7.260, T7.270)
• New Holland T8 Series (T8.275, T8.300, T8.390, T8.410)
• New Holland TM Series (TM175, MXM/TM)

1. 1

   Access the H5 diagnostic menu to check the real-time operation and live voltage reading coming from the Remote No. 2 valve

2. 2

   Inspect the wiring harness between the Arm Rest Module (ARU) / ATC and the Rear Remote No. 2 valve for rubbed-through insulation causing a short to power

3. 3

   Disconnect the plug at the Remote No. 2 valve and check for water ingress, corrosion, or bent pins bridging the voltage supply to the signal return

4. 4

   With the sensor disconnected, check if the over-voltage code changes to an under-voltage or open-circuit code to determine if the potentiometer is internally shorted

1. 1

   Disconnect Power

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

2. 2

   Repair Wiring

   If the diagnostic checks revealed a short in the harness, splice and repair the damaged wires using weather-sealed connectors.

3. 3

   Replace the Potentiometer

   If the wiring tests good, the spool position potentiometer on the Rear Remote No. 2 valve has failed. Remove the retaining screws holding the sensor to the valve slice and install the replacement potentiometer.

4. 4

   Reassembly

   Reconnect the wiring harness to the remote valve.

5. 5

   Calibration

   Reconnect the battery. You must perform a hydraulic remote valve calibration using the tractor's calibration menu. This allows the control module to learn the new potentiometer's specific neutral, extend, and retract voltage limits.