Fendt 06.1.02 – A004 - Control Panel ECU: S020 - Right external 'Rear PTO ON / OFF' pushbutton - Signal fault.

The control unit is receiving an implausible signal, no signal, or a continuous signal from the external PTO switch located on the right rear fender. This is typically caused by a mechanical failure inside the switch (e.g., contacts stuck closed due to dirt/moisture) or an electrical fault in the switch's wiring harness. Operational Consequence: The standard PTO speed selection and external engagement are disabled for safety. However, the PTO can still be engaged in emergency mode by pressing and holding the emergency PTO button in the cab for 5 seconds.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• Fendt 300 Vario series
• Fendt 400 Vario / Farmer 400 series
• Fendt 500 Vario series
• Fendt 700 Vario / Favorit 700 series
• Fendt 800 Vario / Favorit 800 series
• Fendt 900 Vario / Favorit 900 series (including COM III and S4 generations)

1. 1

   Visually inspect the S020 switch on the right rear fender for physical damage or water ingress.

2. 2

   Disconnect the switch's 3-pin AMP Superseal connector and inspect pins for green corrosion, moisture, or pushed-back terminals.

3. 3

   Perform a continuity test on the switch using a multimeter (should be open circuit at rest, and show continuity only when pressed).

4. 4

   Check the wiring harness running from the right fender to the A004 ECU for chafing or pinch points, especially along the axle housing.

1. 1

   Preparation

   Turn off the tractor ignition and disconnect the battery to prevent short circuits.

2. 2

   Access the Switch

   Locate the S020 PTO switch on the right rear fender.

3. 3

   Disconnect Wiring

   Reach behind the fender panel and unplug the 3-pin AMP Superseal electrical connector.

4. 4

   Remove the Faulty Switch

   Squeeze the retaining tabs or remove the locking nut (depending on the exact fender trim) and push the old switch out through the front of the fender panel.

5. 5

   Install the New Switch

   Push the new switch into the 30mm mounting hole until it clicks securely into place.

6. 6

   Reconnect

   Apply a small amount of dielectric grease to the AMP Superseal connector to prevent future moisture ingress, then plug it into the new switch.

7. 7

   Clear Codes

   Reconnect the battery and turn on the ignition. Navigate to the tractor's terminal fault menu. Acknowledge and clear the stored 06.1.02 fault code. (Note: In Fendt systems, clearing the code removes it from the active display; if the physical fault wasn't fixed, the code will immediately return).

8. 8

   Test Operation

   Test the right external PTO button to ensure it engages and disengages the PTO correctly.