Fendt 5.1.91 – A034 - Driving switch (Joystick) / A002 - ECU (Enhanced control): A034 - Driving switch, CAN bus

There is a signal fault originating from the 'Rear automatic system ON/OFF' button located on the joystick (A034). The rear automatic system and the 'Teach-In' functions will not operate, though the tractor can usually continue to be driven in emergency mode or standard manual operation.

• 411 Vario COM III
• 412 Vario COM III
• 413 Vario COM III
• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
• 716 Vario COM III
• 718 Vario COM III
• 818 Vario COM III
• 820 Vario COM III
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III) (e.g., 409, 410, 411, 412)
• Fendt 700 Vario (COM III) (e.g., 711, 712, 714, 716)
• Fendt 800 Vario (COM III) (e.g., 815, 817, 818)
• Fendt 900 Vario (COM III) (e.g., 916, 920, 924, 926, 930)

1. 1

   Inspect the 'Rear automatic ON/OFF' button on the joystick for physical damage, sticking, or debris preventing proper contact.

2. 2

   Verify the CAN bus wiring harness and connectors between the A034 joystick and the A002 Enhanced Control ECU. Look for pinched wires or loose pins.

3. 3

   Check the power supply for the CAN bus located on circuit board A013. Specifically, check fuse F047, which supplies the joystick.

4. 4

   Connect the FENDIAS diagnostic tool to read the A034 drive switch data. Check if the system is throwing concurrent EOL (End of Line) checksum errors or EEPROM initialization errors for the joystick.

1. 1

   Relieve Pressure & Power Down

   Ensure the tractor is turned off and the battery is disconnected. Note: Fendt manuals strictly warn that hydraulic accumulators and suspension cylinders remain pressurized up to 200 bar even with the engine off; ensure you do not disturb hydraulic lines while working in the cab.

2. 2

   Test the Switch

   If possible, test the continuity of the specific button switch on the joystick. If the internal microswitch or the joystick's internal circuit board has failed, the joystick will need to be repaired or replaced.

3. 3

   Remove the Joystick

   Carefully dismantle the armrest trim to access the base of the A034 driving switch. Disconnect the CAN bus plug connection and remove the joystick.

4. 4

   Repair or Replace

   You can either send the joystick to a specialized agricultural electronics repair center (such as Ilgenfritz Mechatronics) or install a new OEM replacement.

5. 5

   Reassembly

   Install the new/repaired joystick and reconnect the CAN bus harness.

6. 6

   EOL Programming

   Crucial Step: According to Fendt service documentation, after replacing the A034 joystick or resolving a CAN communication fault, you must run a new EOL (End of Line) programming sequence using the FENDIAS dealer software to initialize the new joystick on the tractor's CAN network.