Fendt 6.1.15 – A004: A004 - NEUTRAL speed selector key — Key / A004 signal fault.

The system has detected a signal failure or circuit interruption specifically related to the neutral speed selection button for the PTO. Because the system cannot verify the neutral position, the safety protocol is triggered: the PTO speed cannot be modified or selected, automatic mode is ended, and the PTO actively disengages or fails to function.

• 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
• 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 Farmer 400 / 400 Vario (COM III) 409
• Fendt Farmer 400 / 400 Vario (COM III) 410
• Fendt Farmer 400 / 400 Vario (COM III) 411
• Fendt Farmer 400 / 400 Vario (COM III) 412
• Fendt Farmer 400 / 400 Vario (COM III) 413
• Fendt Farmer 400 / 400 Vario (COM III) 414
• Fendt Farmer 400 / 400 Vario (COM III) 415
• Fendt Favorit 700 / 700 Vario (COM III) 711
• Fendt Favorit 700 / 700 Vario (COM III) 712
• Fendt Favorit 700 / 700 Vario (COM III) 714
• Fendt Favorit 700 / 700 Vario (COM III) 715
• Fendt Favorit 700 / 700 Vario (COM III) 716
• Fendt Favorit 700 / 700 Vario (COM III) 717
• Fendt Favorit 700 / 700 Vario (COM III) 718
• Fendt 800 Vario (COM III) 815
• Fendt 800 Vario (COM III) 817
• Fendt 800 Vario (COM III) 818
• Fendt 800 Vario (COM III) 820
• Fendt Favorit 900 / 900 Vario (COM III) 916
• Fendt Favorit 900 / 900 Vario (COM III) 920
• Fendt Favorit 900 / 900 Vario (COM III) 924
• Fendt Favorit 900 / 900 Vario (COM III) 926
• Fendt Favorit 900 / 900 Vario (COM III) 930

1. 1

   Verify the symptom by attempting to select a PTO speed and confirming that the PTO disengages or fails to respond

2. 2

   Check fuses F040 and F041 on the A013 printed circuit board (fuse board) to ensure the A004 control console is receiving proper CAN-Bus voltage

3. 3

   Inspect the CAN connection between the A002 (ECU, enhanced control) and the A004 (ECU, control panel) for line discontinuities or short circuits to earth

4. 4

   Consult the PTO circuit diagram (Sheet 32) to trace the specific wiring for the NEUTRAL speed selector key

5. 5

   Connect the FENDIAS diagnostic tool to monitor A004 control panel inputs and verify if pressing the NEUTRAL speed selector key registers a signal change

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the battery to prevent electrical shorts while working on the control console.

2. 2

   Fuse Replacement

   If fuses F040 or F041 on the A013 board are blown, replace them. Re-test the system; if the fuse blows again, there is a short in the A004 wiring harness.

3. 3

   Access the A004 Console

   Carefully remove the trim and mounting hardware to access the underside/rear of the A004 side control console.

4. 4

   Inspect Wiring and Connectors

   Check the main connectors (e.g., Connector X033) plugging into the A004 console. Look for backed-out pins, corrosion, or chafed wires. Repair any damaged wiring.

5. 5

   Component Replacement

   If the wiring and fuses are perfectly intact but the FENDIAS tool shows no signal from the button, the physical switch or the internal printed circuit board of the A004 console has failed. Depending on the specific chassis number, you will need to replace either the individual neutral switch circuit board or the entire A004 control console assembly.

6. 6

   Reassembly and Clearing Codes

   Reconnect the console and battery. Turn the ignition on, clear the fault codes using FENDIAS, and perform a functional test of the PTO to ensure speeds can now be selected and the PTO remains engaged.