Case IH 4041 – Arm Rest Module (ARU): Supply Voltage too High (>18V) (DV Module Only)

This indicates that the control module is receiving an incoming power supply voltage that exceeds the safe operating threshold of 18 volts. This is typically caused by a failing alternator voltage regulator that is overcharging the electrical system, a wiring short to a higher voltage source, or an internal failure within the module's voltage sensing circuitry.

• Maxxum
• Steiger
• Magnum
• Puma
• Farmall

1. 1

   Alternator Output Test: Start the tractor and use a digital multimeter to measure the voltage across the battery terminals. A healthy charging system should read between 13.5V and 14.5V. If the voltage spikes above 15V (and especially if it approaches or exceeds 18V), the alternator's voltage regulator has failed and is overcharging the system.

2. 2

   ARU Power Supply Test: If the battery voltage is normal, access the Arm Rest Module (ARU) and back-probe the main power supply pins. Compare the voltage at the ARU to the battery voltage.

3. 3

   Wiring Harness Inspection: Inspect the wiring harness routing from the battery/fuse panel to the ARU for any chafing, melting, or shorts to other power wires.

4. 4

   Internal ARU Check: If the multimeter shows a normal 12V-14.5V at the ARU connector, but the ARU is still logging code 4041 (>18V), the module's internal voltage sensor has failed, and the ARU itself must be replaced.

1. 1

   Disconnect battery (Scenario A: Alternator Overcharging)

   Disconnect the battery to prevent electrical arcing.

2. 2

   Remove drive belt

   Release the tension on the engine serpentine/drive belt and remove the belt from the alternator pulley.

3. 3

   Disconnect alternator wiring

   Disconnect the electrical connectors and the main power cable from the rear of the alternator.

4. 4

   Remove alternator

   Unbolt the alternator from its mounting bracket and remove it from the engine bay.

5. 5

   Install new alternator

   Install the new alternator, torque the mounting bolts to OEM spec, and reconnect the wiring.

6. 6

   Verify charging voltage

   Reinstall the drive belt and restore battery power. Start the engine and verify the charging voltage is now below 14.5V.

7. 7

   Disconnect battery (Scenario B: ARU Module Failure)

   Disconnect the battery.

8. 8

   Expose ARU

   Remove the plastic trim panels and covers on the tractor's armrest console to expose the ARU.

9. 9

   Disconnect ARU wiring

   Carefully disconnect the multi-pin wiring harnesses plugged into the ARU.

10. 10

    Remove ARU

    Remove the retaining screws/bolts holding the ARU in place and lift the module out.

11. 11

    Install replacement ARU

    Install the replacement ARU and secure it with the retaining hardware.

12. 12

    Reassemble armrest

    Reconnect all wiring harnesses and reinstall the armrest trim panels.

13. 13

    Clear fault code

    Reconnect the battery. Turn the key on and use a diagnostic scan tool to clear the 4041 fault code. (Note: A new ARU may require dealer calibration/programming to sync with the tractor's main ECU).