Fendt 5.1.91 – Joystick / EPC REAR ACTUATORS: A003, A034 - 'Rear automatic ON / OFF' key in joystick — Signal fault

The system has detected a signal fault or failure from the specific button (key) on the Vario joystick used to toggle the rear automatic mode (typically for the rear PTO or power lift). The rear automatic mode will not function, though the tractor can still be driven.

• 409 Vario
• 410 Vario
• 411 Vario
• 412 Vario
• 711 Vario
• 712 Vario
• 714 Vario
• 715 Vario
• 716 Vario
• 717 Vario
• 718 Vario
• 916 Vario
• 920 Vario
• 924 Vario
• 926 Vario
• 930 Vario
• Farmer 400 Series (409, 410, 411, 412)
• Favorit 700 / 700 Vario Series (711, 712, 714, 716)
• Favorit 900 / 900 Vario Series (916, 920, 924, 926, 930)
• 800 Vario Series (815, 817, 818)
• COM III Generations of the 300, 400, 700, 800, and 900 Vario series

1. 1

   Inspect the 'Rear automatic ON / OFF' button on the joystick for physical damage, sticking, or lack of tactile feedback.

2. 2

   Check the wiring harness and connectors between the joystick (A003/A034) and the tractor's main control module for pinched wires or loose pins.

3. 3

   Check the voltage and current at the joystick connector (e.g., Connector X032_P). The requested supply voltage is typically 8 - 8.5 V.

4. 4

   Connect the FENDIAS diagnostic tool to monitor the live signal from the joystick button. If the button is pressed but no signal change is registered, the internal microswitch or circuit board has failed.

1. 1

   Remove the Joystick

   Disconnect the battery. Carefully remove the armrest covers to access the joystick mounting hardware and wiring harness. Disconnect the joystick's main connector.

2. 2

   Component Repair vs. Replacement

   Repair the joystick by replacing defective microswitches and repairing the internal CAN circuit board, or replace the specific joystick switch plate or the entire joystick assembly.

3. 3

   Reinstallation

   Install the repaired or new joystick, reconnect the wiring harness, and reassemble the armrest.

4. 4

   Calibration / EOL Programming

   After replacing the joystick (A034), an EOL (End of Line) reprogramming or calibration via the FENDIAS diagnostic tool may be required to ensure the tractor's CAN bus properly recognizes the new component. Clear the 5.1.91 fault code and test the rear automatic function.