New Holland NH 4005 – Arm Rest Module (ARU): Signal of Aux-stick (AUX2) out of range low

The electrical signal voltage coming from the secondary auxiliary joystick or paddle (AUX2) has dropped below the minimum acceptable threshold, indicating a failed potentiometer, open circuit, short to ground, or poor connection.

• New Holland T5 Series
• New Holland T6 Series
• New Holland T7 Series
• New Holland T8 Series
• New Holland T9 Series
• New Holland TM Series
• New Holland TVT Series

1. 1

   Inspect the AUX2 joystick/paddle on the armrest for physical damage, sticking, or debris preventing full range of motion.

2. 2

   Access the wiring harness beneath the armrest console. Disconnect the joystick connector and inspect for bent pins, corrosion, or moisture.

3. 3

   Using a multimeter, check the wiring harness between the AUX2 potentiometer and the ARU for continuity. Test for a short to ground, which would pull the signal voltage out of range low.

4. 4

   Measure the resistance or voltage output of the AUX2 potentiometer while moving the stick. The voltage should scale smoothly. If the reading drops out entirely or stays at zero, the potentiometer is internally faulty.

5. 5

   Verify that the ARU is receiving proper supply voltage, as low reference voltage to the sensors can trigger out of range low codes (often accompanied by code 4040: Supply Voltage too low).

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the negative battery terminal to prevent electrical shorts.

2. 2

   Disassemble the Armrest

   Remove the retaining screws holding the upper plastic housing/bezel of the armrest console to expose the internal control modules and joystick assemblies.

3. 3

   Remove the Faulty Joystick

   Disconnect the wiring harness from the AUX2 joystick/potentiometer. Unbolt the joystick assembly from the armrest mounting plate.

4. 4

   Install the Replacement Part

   Mount the new joystick or potentiometer into the armrest plate and secure the hardware. Reconnect the wiring harness, ensuring the connector clicks firmly into place.

5. 5

   Reassemble

   Reinstall the armrest housing and bezel. Reconnect the battery.

6. 6

   Calibration

   Turn the key on. You will likely need to perform an armrest/joystick calibration procedure using the tractor's in-cab digital display (H-Menu) or a dealer electronic service tool so the ARU can learn the new potentiometer's neutral, minimum, and maximum voltage limits.