Fendt A.1.D1 – A002 ECU (Enhanced Control): A034 - Driving switch, CAN bus: Joystick button for spool valve 3 Lifting / Lowering Key fault

Signal fault or physical failure of the specific button on the A034 Driving Switch (Joystick) used to control spool valve 3, resulting in no valve operation available for spool valve 3.

• 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)
• FENDT 700 Vario (COM III)
• FENDT 800 Vario (COM III)
• FENDT 900 Vario (COM III)

1. 1

   Connect the FENDIAS diagnostic program to check the A034 drive switch data and filter data

2. 2

   Verify the CAN bus connection between the A002 ECU (enhanced control) and the A034 Drive switch, ensuring there are no wiring harness breaks or communication faults

3. 3

   Inspect the specific raise/lower button for spool valve 3 on the joystick for physical damage, sticking, or debris

1. 1

   Inspect and clean

   Disconnect the electrical supply and inspect the A034 joystick. Attempt to clean the contacts for the spool valve 3 button if debris is causing the key fault.

2. 2

   Replace component

   If the button is internally shorted or mechanically failed, the A034 Joystick assembly (or the specific button board, depending on the exact joystick revision) must be replaced.

3. 3

   EOL programming

   If the A034 Joystick is replaced, you must run new EOL (End of Line) programming using the FENDIAS diagnostic tool. This teaches the A002 ECU to recognize the new joystick and clears the checksum/initialization errors.