Case IH 18322 (4169.02, 4169.03, 4169.04, 518462.07) - ACML – Armrest Control Module (ACM / ACML): MFH CRPM Toggle Switch ACML - error state

This fault code indicates an error state with the CRPM (Constant RPM) Toggle Switch located on the MFH (Multi-Function Handle). The control module is receiving an implausible signal, an open circuit, or a voltage out-of-range (too high/too low) from this specific switch.

• MAXXUM T4E
• Magnum series (250, 260, 280, 290, 310, 340, 380)
• Puma series (140, 165, 175, 180, 195, 200, 210, 225)
• Models with CVT/CVX or Full Power Shift transmissions

1. 1

   Access the Diagnostic Menu: Connect the diagnostic tool or enter the tractor's onboard diagnostic menu (often referred to as the 'H Menu' or 'HH Menu' on the dot matrix display).

2. 2

   Monitor Switch Inputs: Navigate to the switch input channels to verify if the ACM is recognizing the CRPM switch actuations (d54: CRPM on/off, d55: decrease, d56: increase, d57: selection).

3. 3

   Wiring & Connector Check: Inspect the wiring harness and connectors between the Multi-Function Handle and the Armrest Control Module for damaged pins, corrosion, or chafed wires causing a short or open circuit.

1. 1

   Turn the key start switch OFF.

   Ensure the machine is powered down before proceeding with repairs.

2. 2

   Evaluate switch and wiring.

   If the diagnostic menu shows no change in state when the CRPM switch is toggled, and the wiring harness tests good for continuity, the fault lies within the switch itself.

3. 3

   Replace the Multi-Function Handle (MFH).

   Because the CRPM switch is integrated into the Multi-Function Handle, the repair typically requires replacing the entire MFH assembly.

4. 4

   Replace and reprogram the Armrest Control Module (ACM).

   If the MFH tests good but the signal is lost at the module, the Armrest Control Module (ACM) may require replacement and reprogramming.