Fendt 6.1.02 – Enhanced Control ECU (A002) / Comfort E-box: Signal fault from component S020 (Right external "Rear PTO ON / OFF" pushbutton)

The system detects an electrical or mechanical issue with the switch (such as a short, open circuit, or a button stuck pressed for more than 30 seconds). The external fender button is disabled. The rear PTO can only be engaged in "emergency mode" by pressing and holding the PTO button inside the cab for at least 5 seconds.

• 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
• Fendt Favorit 700 and 900 series
• Fendt 300, 400, 700, 800, and 900 Vario series (including COM III and S4 generations)

1. 1

   Visually inspect the S020 pushbutton on the right rear mudguard for physical damage, heavy dirt ingress, or a stuck mechanism (a button stuck for >30 seconds triggers a fault).

2. 2

   Disconnect the switch and test it with a multimeter to verify if the internal contacts are opening and closing properly when pressed.

3. 3

   Inspect the wiring harness running from the right mudguard switch back to the Enhanced Control ECU (Comfort E-box) for chafed wires, broken connections, or corrosion in the connectors.

1. 1

   Power Down

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

2. 2

   Access the Switch

   Locate the S020 PTO switch on the right rear mudguard. Remove any protective rubber boots or retaining bezels holding the switch in place.

3. 3

   Disconnect

   Unplug the electrical connector from the back of the switch. If the connector is heavily corroded, clean it with electrical contact cleaner.

4. 4

   Replace/Repair

   If the switch failed the continuity test, install a new OEM switch. If the wiring was broken, splice and heat-shrink the damaged section of the harness.

5. 5

   Reassemble

   Plug the connector into the new switch and secure the switch back into the mudguard housing.

6. 6

   Test

   Reconnect the battery and turn on the ignition. Clear the fault codes via the terminal. Test the PTO engagement using the cab button normally, and then test the fender control activation sequence to ensure the S020 button engages and disengages the PTO correctly.