Fendt 4.1.88 – A034 - Joystick: A034 - Joystick — Plausibility error at the ON/OFF key of the accelerator pedal mode

The electronic control system is receiving an irregular, conflicting, or missing signal from the specific button on the joystick used to toggle the accelerator pedal driving mode. As a result, the system registers a plausibility error, the button ceases to function, and the operator will be unable to switch the accelerator pedal mode.

• 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
• Fendt Farmer 400 Vario
• Fendt Favorit 700 Vario
• Fendt Favorit 900 Vario
• Fendt 300 Vario series
• Fendt 400 Vario series
• Fendt 700 Vario series
• Fendt 800 Vario series
• Fendt 900 Vario series

1. 1

   Software Diagnostics: Connect the tractor to the FENDIAS diagnostic program. Navigate to the A034 Joystick module to monitor live data and test the ON/OFF key for the accelerator pedal mode to see if the software registers any state changes when the button is pressed.

2. 2

   Physical Inspection: Check the physical condition of the button on the joystick for sticking, debris, or mechanical failure.

3. 3

   Wiring & CAN Bus: Inspect the wiring harness and CAN bus connections between the A034 Joystick and the A002 Enhanced Control ECU for continuity, corrosion, or damage, as CAN communication faults can sometimes trigger localized plausibility errors.

1. 1

   Park the tractor on a level surface, turn off the engine, and engage the parking brake.

2. 2

   Use the FENDIAS diagnostic tool to confirm the button's failure to change states.

3. 3

   If the wiring and CAN bus connections are intact but the button fails the diagnostic test, the A034 Joystick (or its internal button board) is faulty and must be replaced.

4. 4

   Disconnect the tractor's battery.

5. 5

   Remove the armrest/console trim to access the base of the A034 Vario joystick.

6. 6

   Disconnect the joystick's electrical connector.

7. 7

   Unbolt and remove the faulty joystick assembly.

8. 8

   Install the new OEM joystick and reconnect the wiring harness.

9. 9

   Reconnect the battery and turn the ignition on.

10. 10

    Connect the FENDIAS tool and perform an EOL (End of Line) programming for the new A034 joystick so the tractor's ECU recognizes the new module.

11. 11

    Perform necessary calibrations, such as Calibration Code 4010 (potentiometer 'accelerator pedal range' / sliding switch on the A034 joystick) as specified in the Fendt workshop manual.

12. 12

    Clear the fault codes and test the accelerator pedal mode button for proper operation.