Fendt 08.1.38 – Rear EPC: External buttons lower left and right, rear power lift (S028 and S030) - Button lower line interruption

The system has detected a 'Button lower line interruption', indicating an open circuit, a broken wire, or a complete loss of signal from the external fender buttons used to lower the rear three-point hitch. This results in reduced control performance, inoperable external lower buttons, and a lockout of the external control function until the next trouble-free cold start.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• 300 Vario series
• 400 Vario series
• 500 Vario series
• 700 Vario series
• 800 Vario series
• 900 Vario series
• 300 Vario
• 900 Vario COM III
• Farmer 300
• Favorit 500
• Favorit 700
• Favorit 800
• 200 Vario series
• 1000 Vario S4

1. 1

   Inspect the external rear power lift lower buttons (S028 on the right fender, S030 on the left fender) for physical damage, stuck buttons, or heavy dirt/moisture ingress.

2. 2

   Trace the wiring harness from the external buttons back to the Rear EPC module. Look for chafed wires, pinched harnesses, or broken lines, particularly where the harness routes along the rear fenders and cab suspension points.

3. 3

   Disconnect the switches and check the electrical connectors for corrosion, bent pins, or moisture.

4. 4

   Use a multimeter to test the switch itself. Check for continuity when the button is pressed and an open circuit when released. If the switch fails to close the circuit when pressed, the switch has failed internally.

1. 1

   Safety First

   Park the tractor on a level surface, lower any attached rear implements to the ground (using the in-cab terminal if the external buttons are locked out), turn off the engine, and disconnect the battery.

2. 2

   Access the Switch

   Locate the faulty external lower button (S028 or S030) on the rear fender extension.

3. 3

   Repair Wiring (If Applicable)

   If the diagnostic tests revealed a broken wire in the harness, repair the damaged section using appropriate weatherproof splice connectors and heat shrink tubing.

4. 4

   Remove the Faulty Switch

   If the switch itself is dead, disconnect the electrical connector from the back of the switch. Release the retaining clips or unscrew the mounting nut holding the switch in the fender housing and push it out.

5. 5

   Install the New Switch

   Insert the new OEM replacement switch into the fender housing until it clicks or is securely fastened.

6. 6

   Reconnect

   Apply a small amount of dielectric grease to the electrical connector to prevent future moisture intrusion, then plug it securely into the new switch.

7. 7

   Clear Codes and Test

   Reconnect the battery and start the tractor. Use the tractor's terminal to navigate to the fault code menu and clear the stored 08.1.38 code. Test the external rear power lift buttons to confirm the linkage lowers correctly.