Fendt 7.1.01 – A004 module (Control Console): Front PTO ON / OFF key — Key / A004 signal fault

The system has detected a signal interruption, plausibility error, or communication failure between the front Power Take-Off (PTO) engagement switch and the control console. It often points to a direct failure of the switch itself, a wiring issue, or a CAN-bus communication fault.

• 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
• Farmer 400 series
• Favorit 700 and 900 series
• Fendt 200, 300, 400, 500, 700, 800, 900, and 1000 Vario series (including COM III and SCR/S4 generations)
• Fendt Xylon (520, 522, 524)
• Fendt Katana 65 forage harvesters

1. 1

   Check fuses F040 and F041 on printed circuit board A013 to verify the voltage supply for the CAN-Bus

2. 2

   Inspect the yellow front PTO push button for physical damage, sticking, or dirt ingress (a stuck key for >30 seconds causes a plausibility error)

3. 3

   Check the AMP Superseal 3 x 1.5 connector at the back of the switch to ensure it is securely plugged in, free of moisture, and pins are not corroded

4. 4

   Test CAN-Bus communication between the A004 (Control console) and A002 (Enhanced control ECU) if the switch and wiring are intact

1. 1

   Disconnect Power

   Disconnect the tractor's battery to prevent electrical arcing or accidental engagement during the repair.

2. 2

   Access the Console

   Carefully remove the necessary trim panels on the A004 control console to access the rear of the PTO switch.

3. 3

   Disconnect the Switch

   Unplug the AMP Superseal connector from the back of the faulty front PTO switch.

4. 4

   Remove the Switch

   Pop the faulty 30mm yellow push button switch out of its mounting point in the console.

5. 5

   Install the New Part

   Insert the direct-replacement switch into the console mounting point until it clicks into place.

6. 6

   Reconnect Wiring

   Plug the existing AMP Superseal wiring connector into the new switch.

7. 7

   Test Operation

   Reconnect the battery, turn on the ignition, and test the front PTO engagement to ensure the fault code is cleared and the PTO operates smoothly.