Fendt 8.3.28 – A004 - ECU, control panel: Fault in the rear EPC (Electronic Power Control) quick lift switch

The system has detected a signal line fault, or a mechanical/electrical failure in the switch itself. Consequence: The in-cab 'Raise' and 'Lower' functions for the rear linkage are locked out. The rear power lift can only be operated using the external pushbuttons located on the rear fenders.

• 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 Vario
• Favorit 700 Vario
• Favorit 900 Vario
• Fendt 300 Vario series
• Fendt 400 Vario series
• Fendt 700 Vario series
• Fendt 800 Vario series
• Fendt 900 Vario series

1. 1

   Verify external operation by testing the external rear power lift buttons on the fenders to isolate the issue to the A004 cab console

2. 2

   Connect the FENDIAS diagnostic tool and monitor the live signal from the quick lift switch under 'REAR EPC ACKNOWLEDGEMENTS / STATUS' or 'REAR EPC ACTUATION/STATUS'

3. 3

   Inspect the quick lift switch on the A004 control console for physical damage, sticking, or debris

4. 4

   Check the wiring harness and connectors between the A004 control panel and the main bus for continuity, loose pins, or shorts

1. 1

   Replicate the Fault

   Attempt to use the in-cab rear EPC quick lift switch. Confirm that the system is locked and only responds to external fender buttons.

2. 2

   Disconnect Power

   Turn off the ignition and disconnect the battery before servicing cab electrical components.

3. 3

   Access the A004 Console

   Carefully remove the trim and mounting screws to access the underside of the A004 control console (operating console) located on the right-hand armrest/side panel.

4. 4

   Inspect Connections

   Disconnect the main harness to the A004 console. Inspect for corrosion, pushed-out pins, or wire chafing. Clean the contacts with electrical contact cleaner.

5. 5

   Test the Switch

   Using a multimeter, test the quick lift switch for proper electrical continuity across its positions (Raise/Neutral/Lower) as per the OEM circuit diagram.

6. 6

   Replace Component

   If the switch fails the continuity test or is mechanically broken, replace the switch. Note: On many Fendt Vario models, the quick lift switch is integrated into the linkage control module or the A004 control console itself, requiring the replacement of the module rather than just the switch.

7. 7

   Reassemble and Clear Codes

   Reconnect the console and battery. Turn on the ignition, clear the stored 8.3.28 fault code via the Varioterminal or FENDIAS, and test the in-cab quick lift switch for proper operation.