Fendt 6.1.B7 – A004 - ECU, control panel: A004 - ECU, control panel; 750 rpm speed selector key. Communication fault.

A communication error or signal failure originating from the button used to select the 750 rpm speed for the rear PTO. The system is either not receiving a valid signal when the button is pressed, or the button's circuit is experiencing an electrical fault (such as an open circuit or a stuck/shorted switch). As a consequence, the 750 rpm rear PTO speed cannot be engaged, and the system defaults to a restricted or emergency operating mode for the PTO.

• 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 series
• Fendt Favorit 700 and 900 series
• Fendt 300 Vario series
• Fendt 400 Vario series
• Fendt 700 Vario series
• Fendt 800 Vario series
• Fendt 900 Vario series

1. 1

   Inspect the 750 rpm PTO speed selector button on the A004 control console to see if it is physically stuck, damaged, or failing to return to its neutral position.

2. 2

   Check if other buttons on the A004 control panel are functioning to rule out a broader CAN bus communication failure (e.g., if code 6.1.B8 is also present).

3. 3

   Inspect the wiring harness connecting the A004 control panel to the tractor's main harness for pinched wires, corrosion at the connectors, or loose pins.

4. 4

   Connect the FENDIAS diagnostic tool to monitor the live state of the A004 control panel and observe the signal status of the 750 rpm key.

1. 1

   Power Down

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

2. 2

   Access the Console

   Carefully remove the trim and retaining screws to access the underside of the A004 control panel (side console/armrest).

3. 3

   Inspect Connectors

   Disconnect the electrical plugs leading to the PTO speed selector keypad. Clean the contacts with electrical contact cleaner and ensure no pins are backed out of the connector housing.

4. 4

   Component Replacement

   If the wiring is sound but the button fails continuity testing (or fails to register in FENDIAS), the switch has failed internally. Depending on the specific tractor model's console design, you must replace either the modular PTO speed selector switch assembly or the integrated A004 control panel keypad.

5. 5

   Reassembly

   Reconnect the wiring harnesses and reinstall the A004 control panel into the armrest.

6. 6

   Clear Codes and Test

   Reconnect the battery and turn on the ignition. Use the tractor's Varioterminal or the FENDIAS tool to clear the stored 6.1.B7 fault code. Start the tractor and test the rear PTO to ensure the 750 rpm speed engages successfully.