CLAAS 7F3Dh – BDG: Function 3 and 4 Button Message Missing

A communication breakdown on the CAN bus where the message from the Function 3 and 4 buttons (typically located on the CMOTION joystick or multifunction armrest) is not received by the BDG (A103) module. The system logs this fault and disables the associated functions as a safety measure until the communication is restored.

• Axion 810
• Axion 850
• Axion Series
• Arion Series

1. 1

   Use the CEBIS terminal to check for active and stored error codes to confirm the presence of 7F3Dh or related communication faults

2. 2

   Examine the Function 3 and 4 buttons on the joystick or armrest for physical damage, sticking, or excessive wear

3. 3

   Inspect the wiring harnesses and connectors to the multifunction armrest and joystick for loose connections, corrosion, or physical damage. Disconnecting and reconnecting the main connectors to the armrest module can sometimes re-establish communication.

4. 4

   Verify power and ground connections to the armrest control module, including fuses and power supply

5. 5

   Test the buttons using a multimeter to ensure electrical contact, or use the CLAAS Diagnostic System (CDS) to monitor the CAN bus network

1. 1

   Disconnect battery

   Before starting any repair, disconnect the machine's battery to prevent electrical shorts.

2. 2

   Access internal components

   Disassemble the joystick or armrest housing by removing the Torx or Allen screws to gain access to the internal wiring and the back of the function buttons.

3. 3

   Inspect internal wiring

   Carefully inspect the internal wiring for any breaks, frayed wires, or loose solder joints connecting the buttons to the control board.

4. 4

   Replace faulty button

   If a button is faulty, desolder the wires from the old switch and solder them to the new one, noting the orientation of the wires before removal.

5. 5

   Repair or replace joystick/module

   If the issue is within the joystick's internal electronics or the armrest module (MFA A100), repair or replace the entire joystick assembly or control module.

6. 6

   Reassemble and test

   Reassemble the components, reconnect the battery, start the machine, clear the fault codes using the diagnostic system, and test the functionality of buttons 3 and 4.