Case IH 518434-13 - ACM – Armrest Control Module (ACM) / Armrest ECU: Multi function handle keypad sensor disagreement

This code indicates that the control module is receiving conflicting or illogical signals from the keypad sensors located on the Multi-Function Handle (MFH). This typically occurs when internal switches or the encoder circuit inside the joystick fail, sending a signal that two mutually exclusive buttons are pressed simultaneously, or that a button's electrical state does not match its expected baseline voltage.

• MAGNUM AFS Connect
• Magnum series
• Steiger series
• Puma series
• Optum series
• Maxxum series
• Flagship Axial-Flow series (140 and 240 series)
• WD4 series

1. 1

   Check Armrest Connections: Remove the armrest covers and inspect the physical wiring harness connecting the Multi-Function Handle to the Armrest Control Module (ACM). Look for loose connectors, backed-out pins, or chafed wires.

2. 2

   Monitor Switch States: Connect the CNH Electronic Service Tool (EST) to the diagnostic port. Monitor the live data for the MFH keypad to see if a specific button is stuck in the 'Closed/Pressed' state or fluctuating erratically.

3. 3

   Check for Related Codes: Look for accompanying ACM fault codes that point to a specific circuit failure, such as 18007 (switch error), 18008/18009 (voltage too low/high), or 18013 (encoder position error).

4. 4

   Test for Grounding Issues: Ensure the armrest module is properly grounded, as bad cab grounds can cause erratic sensor disagreements.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent short circuits.

2. 2

   Disassemble the Console

   Remove the retaining screws for the right-hand armrest control console trim/covers to expose the base of the joystick.

3. 3

   Disconnect the MFH

   Locate and unplug the main electrical connector routing from the Multi-Function Handle to the Armrest Control Module.

4. 4

   Remove the Handle

   Unbolt the mounting hardware securing the base of the Multi-Function Handle to the armrest frame and remove the faulty unit.

5. 5

   Install the New Handle

   Seat the replacement MFH into the armrest, secure the mounting bolts, and plug the connector into the ACM harness.

6. 6

   Reassemble and Calibrate

   Reinstall the armrest covers and reconnect the battery. Connect the EST laptop to clear the inactive 518434-13 fault code. Depending on the machine model, you may need to perform a joystick/SCV calibration via the Pro 700/1200 display or EST to sync the new handle's travel limits with the ACM.