Fendt 00.0.05 – A002 - ECU, enhanced control / A050 - ECU, basic control unit: Bus fault AR/Diff / Bus error 4WD/diff.

CAN bus communication failure specifically related to the All-Wheel Drive (4WD) and Differential Lock activation circuits. When this code is active, the tractor will typically display a warning, and the 4WD/Differential lock functions will become non-operational.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• 200 V/F/P Vario series
• 300 Vario (including COM III)
• 400 Vario (including COM III)
• 700 Vario (including COM III and SCR)
• 800 Vario (including COM III)
• 900 Vario (Favorit, COM III, and SCR)

1. 1

   Check the CAN-Bus power supply on the A013 printed circuit board (fuse board), specifically testing fuses F040 and F041 for the electronics voltage supply.

2. 2

   Inspect the CAN bus wiring harness between the A002/A050 ECU and the 4WD/Differential lock switches (A004 control console) and solenoid valves (Y009 4WD clutch solenoid valve).

3. 3

   Check if the ECU has lost its configuration data and requires EOL (End-Of-Line) programming.

1. 1

   Verify Fuses

   Locate the A013 fuse board and replace fuses F040 or F041 if blown. If they blow immediately upon replacement, trace the 4WD/Diff circuit for a short to ground.

2. 2

   Test CAN Communication

   Using a multimeter or oscilloscope at the ECU separation points, verify the CAN High and CAN Low voltages to ensure the bus is not shorted or open.

3. 3

   Clear the Fault Memory

   Fault codes are stored in the A007 (Instrument panel) and the A050/A002 (Basic Control ECU). Faults in the A050 ECU must be deleted using FENDIAS diagnostic software, while instrument panel codes can sometimes be cleared via the terminal buttons (pressing A, B, and C simultaneously).

4. 4

   EOL Reprogramming

   If the wiring is intact and the voltage supply is correct, connect the tractor to the FENDIAS diagnostic tool and perform an EOL reprogramming of the A002/A050 ECU to restore the 4WD/Diff parameters.

5. 5

   ECU Replacement/Repair

   If the ECU fails to take programming or has an internal hardware fault, the A002/A050 module must be removed and either sent to a specialized agricultural electronics repair facility or replaced entirely.