Fendt 7.1.A1 – ENHANCED CONTROL (ECU A002) / COMFORT FRONT PTO: A004 - Front PTO 'ON' key — Communication fault

This code indicates a communication or signal failure between the Front PTO 'ON' switch (located on the A004 Control Console) and the tractor's electronic control system. The system is unable to verify the status of the Front PTO switch, which will typically result in the Front PTO being inoperable or locked out for safety.

• 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 Farmer 400 Vario series (409, 410, 411, 412)
• Fendt Favorit 700 Vario series (711, 712, 714, 716)
• Fendt Favorit 900 Vario series (916, 920, 924, 926, 930)
• 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

   Check the Switch for Sticking: Verify that the physical button on the A004 console is not mechanically stuck, jammed with debris, or damaged (a related plausibility error Code 7.1.41 triggers if pressed for more than 30 seconds).

2. 2

   Verify CAN Bus Power Supply: Check the voltage supply for the CAN-Bus on the A013 printed circuit board (fuse board). Specifically, inspect fuses F040 and F041.

3. 3

   Inspect Wiring and Connectors: Check the wiring harness and connectors between the A004 Control Console (in the cab on the right mudguard) and the A002 Enhanced Control ECU for pinched wires, corrosion, or loose pins.

4. 4

   Run FENDIAS Diagnostics: If available, use the FENDIAS diagnostic tool to monitor the live state of the A004 console switches to see if the ECU registers any input when the button is pressed.

1. 1

   Power Down

   Turn off the tractor and disconnect the battery before working on the electrical system.

2. 2

   Fuse Replacement (If Applicable)

   If fuses F040 or F041 on the A013 board are blown, replace them and retest the system. If they blow again, there is a short in the CAN bus wiring or the console itself.

3. 3

   Console Removal

   If the wiring and fuses are intact but the switch is unresponsive or throwing the communication fault, remove the paneling on the right mudguard inside the cab to access the A004 Control Console.

4. 4

   Component Repair/Replacement

   The Front PTO switch is integrated into the A004 Control Console keypad. In most cases, if the internal circuit board or switch contact has failed, the A004 console must be sent to an agricultural electronics specialist (like Ilgenfritz Mechatronics) for board-level repair, or the entire console must be replaced.

5. 5

   Reassembly and Clearing Codes

   Install the repaired or new A004 console. Reconnect the battery, turn the key on, and use the tractor's terminal or FENDIAS to clear the stored 7.1.A1 fault code. Test the Front PTO engagement to ensure the repair was successful.