Fendt 1.2.25 – EDC (Electronic Diesel Control) module: K020 - Ub30 EDC relay — Contact does not open, earth contact

The K020 relay (which supplies power to the EDC) is stuck in the closed position or its control circuit is shorted to ground, causing power to continue to be drawn when the tractor is shut off, which will discharge the battery.

• 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
• Fendt Farmer 400 Vario series
• Fendt Favorit 700 Vario series
• Fendt Favorit 900 Vario series (chassis number 23/3001 and up)
• Fendt 300, 400, 700, 800, and 900 Vario (COM III) series

1. 1

   Locate the K020 relay at the right rear in the cab behind the removable cover.

2. 2

   Consult the 'EDC Control' circuit diagram (Chapter 2000 Reg.B) to trace the wiring path.

3. 3

   Pull the K020 relay and test it with a multimeter for continuity across the load pins when unpowered to check if internal contacts are welded/stuck closed.

4. 4

   Check the relay socket and the wiring harness leading to the EDC module for a short to ground (earth contact).

1. 1

   Disconnect the Battery

   Disconnect the negative battery terminal to prevent further battery drain and protect the electrical system during testing.

2. 2

   Access the Relay Panel

   Go to the right rear of the tractor cab and remove the electrical panel cover.

3. 3

   Identify K020

   Locate the relay designated as K020 (EDC UB 30 relay).

4. 4

   Inspect and Replace

   Remove the relay. Inspect the socket terminals for heat damage, melting, or corrosion. If the relay is stuck closed (as diagnosed above), replace it with a new unit.

5. 5

   Repair Wiring (if applicable)

   If the relay was not the issue, trace the ground wire from the K020 socket to the EDC module. Repair any chafed wires that are shorting to the tractor chassis.

6. 6

   Reassemble and Clear Codes

   Install the new relay, replace the panel cover, and reconnect the battery. Turn the ignition on and use the tractor's terminal to clear the stored 1.2.25 fault code.

7. 7

   Verify Repair

   Turn the tractor off and verify with a multimeter that there is no longer a parasitic draw on the battery from the EDC circuit.