New Holland NH 4002 – Arm Rest Module (ARU): Signal of Aux-stick (AUX1) out of range high

This indicates that the electrical signal (voltage) coming from the auxiliary joystick or paddle that controls remote valve #1 (AUX1) is exceeding the maximum permissible threshold. This condition is typically caused by a short circuit to power, an open ground circuit in the wiring harness, or a failed internal potentiometer/sensor within the joystick assembly itself.

• T5 Series
• T6 Series
• T6000
• T6050
• T6070
• T7 Series
• T7000
• T7.170
• T7.185
• T7.210
• T8 Series
• T8.275
• T8.300
• T8.390
• T9 Series
• T9.450
• T9.560

1. 1

   Physical Inspection: Check the physical condition of the AUX1 joystick/paddle on the armrest. Ensure it returns to the neutral position smoothly and is not physically jammed or damaged.

2. 2

   Wiring & Connector Check: Inspect the wiring harness and connectors between the AUX1 joystick and the Arm Rest Module (ARU). Look for chafed wires, corrosion, or loose pins that could cause an open circuit or a short to a 12V/5V power source.

3. 3

   Voltage Supply Test: Verify that the supply voltage to the ARU is within the normal operating range (typically between 8V and 18V). Supply voltage issues can sometimes cause erratic sensor readings.

4. 4

   Live Data Monitoring: Use a diagnostic scan tool or the tractor's onboard diagnostic display to monitor the live data for the AUX1 input. If the voltage is stuck high and does not change when the stick is moved, the internal potentiometer is likely dead or the ground is lost.

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical shorts during the repair.

2. 2

   Access the ARU

   Remove the armrest cover and console panels to access the underside of the joystick and remote valve paddles.

3. 3

   Disconnect the Joystick

   Unplug the electrical connector specifically routed to the AUX1 joystick/paddle.

4. 4

   Harness Repair (If Applicable)

   If the wiring was found to be damaged during diagnostics, repair the broken wires or replace the affected harness section.

5. 5

   Replace the Joystick

   If the wiring is intact, the joystick itself has failed. Remove the mounting screws or bracket holding the faulty AUX1 joystick assembly. Install the new joystick and secure it with the mounting hardware.

6. 6

   Reassembly

   Reconnect the electrical connector and reinstall the armrest console panels.

7. 7

   Calibration

   Reconnect the battery. Turn the key on and use the tractor's onboard display or a diagnostic service tool to clear the NH 4002 fault code. Perform the joystick/remote valve calibration procedure so the ARU can learn the new sensor's neutral, minimum, and maximum voltage limits.