Case IH 1120 – Armrest Controller: MFD Switch Failure

The controller is receiving an out-of-range, missing, or shorted signal from the Mechanical Front Drive (MFD) switch.

• MX Magnum
• Case IH MX / TG Series
• Case IH Magnum Tractors (MX210, MX230, MX255, MX285, MX305)
• Case IH STX Steiger Series

1. 1

   Check for companion code ARM 1069. If present, follow the corrective action for that specific code first, as it may be the root cause.

2. 2

   Remove the controller cover from the rear of the tractor and inspect the wire harness routing. Ensure no wires are loose, pinched, or draped in front of the controllers.

3. 3

   Perform a Controller LED Test: Turn the ignition key to the ON position and observe the LED lamp on the PTO controller. If flashing OFF and ON, the controller is normal. If ON STEADY, the controller has suffered a hardware or software execution failure.

1. 1

   Resolve Wiring Issues

   If the harness was found to be loose or rubbing during the diagnostic inspection, repair any damaged wires and secure the harness tightly against the cab.

2. 2

   Replace the MFD Switch

   Disconnect the battery, remove the armrest control panel trim, unplug the failed MFD switch, and install the replacement.

3. 3

   Replace the Controller

   If the controller LED test resulted in a STEADY ON light (indicating a small chance of a software execution error or internal failure), the controller itself must be replaced.

4. 4

   Clear and Verify

   Reassemble the armrest and rear controller cover. Turn the key ON, clear the inactive fault codes, and test the MFD engagement to ensure the code does not return.