New Holland NH 4185 – Armrest Controller (ARU - Armrest Unit) or EHR (Electronic Hydraulic Remote) control module: EHR Joystick potentiometer X short circuit.

This fault code indicates that the control system has detected a short circuit in the X-axis (left/right movement) potentiometer of the Electro-Hydraulic Remote (EHR) joystick. The signal voltage is out of the expected range, rendering the X-axis control of the hydraulic remotes inoperative.

• T5
• T6
• T7
• T8
• T9
• T6000
• TG
• TM

1. 1

   Inspect the EHR joystick and the wiring harness routed through the armrest for pinched wires, chafing, or exposed copper that could cause a short to ground or voltage.

2. 2

   Disconnect the joystick harness connector and inspect the pins for bending, corrosion, or moisture ingress.

3. 3

   Probe the X-axis potentiometer circuit with a multimeter and measure the resistance across the pins to determine if the internal sensor has failed.

4. 4

   Verify that the armrest controller is communicating properly with the main ECU, checking for accompanying CAN-bus communication codes (e.g., NH 4190 - NH 4193).

1. 1

   Power Down

   Turn off the tractor and disconnect the negative battery cable to prevent electrical spikes during the repair.

2. 2

   Access the Joystick

   Remove the retaining screws on the armrest control panel cover to access the internal EHR joystick assembly.

3. 3

   Disconnect

   Unplug the electrical harness connector from the EHR joystick.

4. 4

   Replace Component

   If the wiring harness tests fine but the potentiometer is internally shorted, the joystick assembly must be replaced. Remove the mounting hardware holding the joystick assembly and remove the faulty unit.

5. 5

   Install New Part

   Mount the replacement joystick assembly into the armrest and reconnect the electrical harness.

6. 6

   Reassemble

   Reinstall the armrest cover and reconnect the battery.

7. 7

   Calibration

   Turn the ignition key on. You must perform an EHR joystick and remote valve calibration procedure using the tractor's display monitor (e.g., IntelliView) or a dealer diagnostic tool to allow the controller to learn the neutral, minimum, and maximum voltage values of the new potentiometer.