New Holland NH 4006 – ARU (Arm Rest Module / Armrest Control Unit): Signal of Aux-stick (AUX2) out of range high

The voltage signal returning from the Auxiliary 2 (AUX2) joystick/potentiometer has exceeded the maximum expected threshold programmed into the controller. This condition is almost always caused by an open ground circuit on the sensor wiring, a short circuit to a 5V reference or 12V power source on the signal wire, or an internal hardware failure of the AUX2 potentiometer itself.

• T5
• T6
• T7
• T8
• T9
• TG210
• TG255
• TG285
• TM series
• T6.140
• T6080
• T7050
• Puma series
• Magnum series

1. 1

   Remove the right-hand armrest console cover and visually inspect the wiring harness leading to the AUX2 joystick for pinched wires, chafing, or disconnected plugs.

2. 2

   Disconnect the AUX2 joystick and inspect the connector pins for corrosion, moisture, or pushed-back terminals.

3. 3

   Test the ground pin at the joystick connector with a multimeter. An open ground is the most common cause of an 'out of range high' code.

4. 4

   With the key ON (engine off), probe the signal wire to ensure it is not shorted directly to the 5V reference or 12V supply.

5. 5

   Use the tractor's 'H Menu' or a CNH Electronic Service Tool (EST) to view the live voltage of the AUX2 stick. If the voltage is pegged at maximum (e.g., 4.5V - 5.0V) and drops to 0V when unplugged, the potentiometer has failed internally.

1. 1

   Power Down

   Turn off the tractor, remove the key, and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Access the ARU

   Remove the retaining screws for the right-hand armrest control panel/console to expose the underside of the remote valve joysticks.

3. 3

   Wiring Repair

   If the diagnostic checks revealed an open ground or shorted wire in the armrest harness, splice and repair the damaged section using heat-shrink connectors.

4. 4

   Replace the Joystick/Potentiometer

   If the wiring is intact, the AUX2 potentiometer/joystick unit must be replaced. Disconnect the electrical harness, remove the mounting screws/nuts securing the joystick to the armrest plate, install the new joystick assembly, secure the hardware, and reconnect the electrical harness.

5. 5

   Reassembly

   Reinstall the armrest console cover.

6. 6

   Calibration

   Reconnect the battery. Power on the tractor and perform the EHR (Electro-Hydraulic Remote) joystick calibration procedure via the tractor's instrument cluster or diagnostic tool. The ARU must learn the new minimum, maximum, and neutral voltage values of the replacement potentiometer to clear the NH 4006 code.