Fendt A.1.D1 – FENDT control unit / Tractor electronic system: Key fault / signal disturbed (Raising / Lowering of spool valve 3)

Fault code A.1.D1 indicates a 'Key fault' or 'signal disturbed' related to the joystick button (components A003, A034) responsible for the Raising / Lowering of spool valve 3. It is an electrical or CAN bus communication error originating from the driving switch. When this code is active, the tractor's safety protocols engage, resulting in 'No valve operation available' for that specific spool valve.

• 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 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Farmer 400
• Fendt 700 Vario (COM III)
• Favorit 700
• 711
• 712
• 714
• 716
• Fendt 800 Vario (COM III)
• 815
• 817
• 818
• Fendt 900 Vario (COM III)
• Favorit 900
• 916
• 920
• 924
• 926
• 930

1. 1

   Check the physical condition of the spool valve 3 button on the joystick (A003/A034) to ensure it is not physically stuck, broken, or contaminated with dirt.

2. 2

   Using an adaptor box and multimeter, check the voltage supply between the Joystick A003 (Pin 30, Connector X032_P) and earth. The requested value should be between 8.0 V and 8.5 V.

3. 3

   Check the fuse board on the side console (A004). Specifically, inspect fuse A013 (Fuse 4, 5, or 8 depending on the exact model year), which supplies the 8.5V power to the transmission/joystick controls.

4. 4

   Inspect the wiring harness for disruptions or short circuits between the Joystick (A003), the Side Console (A004, Connector X033), and the EST Control module (A002, Connector X031).

5. 5

   If available, use the FENDIAS diagnostic software to monitor the live signal of the memory key/button to see if the CAN bus is registering the button press.

1. 1

   Power Down

   Turn off the tractor ignition and disconnect the battery to prevent electrical shorts during disassembly.

2. 2

   Isolate the Defect

   Determine if the failure is just the plastic button cap, the switch plate, or the internal joystick microswitch.

3. 3

   Button Replacement

   If only the external plastic button is broken or missing, carefully pry out the old button and snap a replacement color-coded button (red or green) into the joystick housing.

4. 4

   Joystick Disassembly

   If the internal switch is faulty, remove the Vario drive lever/joystick assembly from the side console armrest.

5. 5

   Disconnect Harness

   Unplug the main connector (X032_P) from the bottom of the joystick.

6. 6

   Replace Component

   Depending on part availability, replace the specific joystick switch plate or the entire Vario joystick assembly.

7. 7

   Reassembly

   Reconnect the wiring harness and securely mount the joystick back into the side console.

8. 8

   Calibration/Clearing

   Reconnect the battery, turn on the ignition, and use the tractor's terminal to clear the stored A.1.D1 fault code. Test the raising and lowering function of spool valve 3 to confirm the repair.