New Holland NH 14904 – Arm Rest Module (ARU): Arm Rest Module (ARU) missing. (Steyr 16x16 only)

This is a CAN Bus communication fault indicating that the main instrument cluster (or Central Control Unit) has lost communication with the Arm Rest Module (ARU), which typically results in all armrest functions being disabled.

• New Holland tractors with Steyr 16x16 transmission
• New Holland T7 series
• New Holland T7.175
• New Holland T7.190
• New Holland T7.210
• New Holland TL90a

1. 1

   Perform a CAN Bus network test to verify if the instrument cluster can communicate with other modules (to rule out a network-wide short or open)

2. 2

   Inspect the wiring harness routing from the cab floor up into the armrest, specifically looking for chafed wires, pinch points, or severed cables at the armrest pivot point

3. 3

   Disconnect the main harness at the ARU and check for pushed-out pins, corrosion, or moisture inside the connector

4. 4

   Verify that the ARU is receiving proper 12V supply voltage and has a clean ground, checking for any blown fuses

1. 1

   Power Down

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

2. 2

   Access the ARU

   Remove the plastic covers on the right-hand multifunction armrest console to expose the Arm Rest Module (ARU).

3. 3

   Test the Circuit

   Using a multimeter, probe the harness connector for the ARU. Confirm 12V power on the supply pins and continuity to ground. Test the CAN High and CAN Low pins for proper resistance (typically 60 ohms across the network when powered down).

4. 4

   Repair Wiring

   If a break or short is found in the armrest pivot wiring, repair the damaged section of the harness using proper splice connectors and heat shrink, or replace the armrest sub-harness.

5. 5

   Replace the ARU

   If power, ground, and CAN lines are all intact but the module still fails to communicate, the ARU has internally failed. Unbolt the faulty ARU and install the replacement module.

6. 6

   Calibration/Programming

   Reconnect the battery and turn the ignition ON. A new ARU will likely require configuration and calibration using the CNH Electronic Service Tool (EST) to match the specific hydraulic and transmission options of the tractor. Clear all stored EEPROM error codes after configuration.