Massey Ferguson 03.03.1A – MFA (Multi-Function Armrest): CAN Bus Message From Spool Valve Controls 1 And 2 On Arm Rest (MFA)

Communication failure on the CAN bus network between the armrest's main controller and the physical fingertip controls used to operate auxiliary hydraulic spool valves 1 and 2. The controller is either receiving an erratic/invalid signal or has lost communication entirely with the control switches.

• 7724S
• 5712SL
• 7722
• 7722S
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7726S
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626

1. 1

   Test if the spool valves can be operated manually or via external fender buttons to isolate the issue to the armrest electronics

2. 2

   Open the armrest console and inspect the internal wiring harness connecting the spool valve controls to the main MFA board for pinched, chafed, or broken wires

3. 3

   Disconnect the plugs at the spool valve controls and inspect for bent pins, loose terminals, or corrosion

4. 4

   Using a multimeter, verify the CAN High and CAN Low lines for continuity, shorts to ground, or shorts to power

5. 5

   Verify that the spool valve control unit is receiving stable operating voltage (5V or 12V) and has a solid ground connection

1. 1

   Disconnect Power

   Turn off the tractor and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Access the MFA

   Remove the retaining screws on the top/side covers of the Multi-Function Armrest to expose the internal electronic components.

3. 3

   Repair Wiring

   If the diagnostic checks revealed a broken wire or damaged connector pin on the CAN bus lines, repair the harness using OEM-approved waterproof splices or replace the damaged connector pigtail.

4. 4

   Replace the Control Unit

   If the wiring and voltages are perfectly intact, the internal circuitry of the spool valve control unit has failed. Unplug the harness from the faulty control unit, unbolt the module from the armrest bezel, install the new control unit, secure the mounting screws, and reconnect the wiring harness.

5. 5

   Reassembly

   Carefully route the wiring to ensure it won't be pinched by the armrest plastics, and reinstall the armrest covers.

6. 6

   Calibration

   Reconnect the battery. Connect the AGCO Electronic Diagnostic Tool (EDT) to clear the 03.03.1A fault code. Run a calibration routine for the new spool valve controls so the MFA learns the new zero/center positions and maximum travel angles.