New Holland NH 4041 – Arm Rest Module (ARU): Supply Voltage too High

The supply voltage to the control module has exceeded the maximum safe threshold (>18V).

• T6 series
• T7 series
• T8 series
• T9 series
• TM series
• Magnum series
• Steiger series

1. 1

   System Voltage Check: Start the engine and use a multimeter to measure the voltage at the battery terminals. If the voltage is spiking above 15V (and especially if it is reaching the >18V threshold), the alternator's voltage regulator has failed and is overcharging the system.

2. 2

   Harness Inspection: Inspect the wiring harness leading to the Arm Rest Module. Look for chafed wires that could be shorting the ARU's power supply line to a higher voltage source.

3. 3

   Pin-Point Voltage Test: Measure the voltage directly at the power supply pins on the ARU connector. If the multimeter reads normal system voltage (12.6V - 14.4V) but the ARU is still logging the 4041 (>18V) fault, the internal voltage-sensing circuitry inside the ARU has failed.

1. 1

   Disconnect Power

   Always disconnect the negative battery terminal before servicing electrical components to prevent further damage.

2. 2

   Address Overcharging (If Applicable)

   If your diagnostic checks revealed system voltage exceeding 15V-18V, remove the drive belt, disconnect the alternator wiring, and replace the alternator (or the internal voltage regulator, if serviceable).

3. 3

   Repair Wiring (If Applicable)

   If a short to power was found in the harness, cut out the damaged section of wiring, solder in a new section of the correct gauge, and seal it with heat-shrink tubing.

4. 4

   Replace the ARU (If Applicable)

   If the system voltage is normal but the ARU internally reads it as too high: Remove the trim panels on the right-hand armrest console, carefully disconnect the multi-pin connectors from the ARU, unbolt the ARU from its mounting bracket and install the replacement module. Note: A new ARU may require calibration or flashing using the CNH Electronic Service Tool (EST) to pair it with the tractor's main controller.

5. 5

   Clear Codes

   Reconnect the battery, turn the key to the ON position, and use a diagnostic tool to clear the inactive NH 4041 fault code.