Fendt 06.1.03 – Enhanced Control ECU (A002): Signal fault / Faulty button (Left external 'Rear PTO ON / OFF' pushbutton S019)

The system receives an implausible signal from the left external 'Rear PTO ON / OFF' pushbutton (S019), often caused by a mechanical or electrical fault such as the button being physically stuck, short-circuited by water/dirt, or continuously pressed for more than 30 seconds. As a safety consequence, the PTO disengages and external speed selection is disabled.

• 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 200 Vario (V/F/P series)
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III, SCR)
• Fendt 800 Vario (COM III)
• Fendt 900 Vario (COM III, S4, SCR)

1. 1

   Perform an emergency override test by pressing the emergency PTO button in the cab for 5 seconds to verify if the PTO engages, isolating the issue to the external S019 switch circuit

2. 2

   Visually inspect the left rear fender switch (S019) for physical damage, heavy dirt ingress, or a stuck button mechanism

3. 3

   Access the back of the switch under the fender and check the wiring harness (connector X229) for corrosion, moisture, or broken wires

4. 4

   Test the switch with a multimeter for continuity to ensure it opens and closes correctly when pressed and released, and is not internally shorted

1. 1

   Preparation

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

2. 2

   Access the Switch

   Locate the S019 external PTO switch on the left rear fender. You may need to remove the protective mudguard/shielding under the fender to access the rear of the switch housing.

3. 3

   Disconnect

   Unplug the electrical wiring harness connector (X229) from the back of the switch.

4. 4

   Removal

   Squeeze the retaining clips or unscrew the locking collar holding the switch to the fender housing, and push the old switch out.

5. 5

   Installation

   Insert the new replacement switch into the fender cutout until it clicks securely into place.

6. 6

   Reconnection

   Reconnect the electrical harness, ensuring the weather seal is intact to prevent future water ingress. Reinstall any protective shielding.

7. 7

   Clear Codes

   Reconnect the battery, turn on the ignition, and clear the stored fault codes via the tractor's terminal or FENDIAS diagnostic software.

8. 8

   Testing

   Test the external PTO button to confirm proper engagement and disengagement.