Fendt 00.0.05 – A050 - Basic Control Unit ECU (EXT): Bus fault AR/Diff (All-Wheel Drive / Differential lock)

Communication failure on the CAN bus network specifically related to the All-Wheel Drive (AWD) and Differential Lock systems. The associated functions become non-operational, and there is no display for these functions on the terminal.

• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• 200 Vario (V, F, P, S series)
• 300 Vario
• 400 Vario (including COM III)
• 500 Vario
• 700 Vario (including COM III, SCR)
• 800 Vario (including COM III, S4)
• 900 Vario (including COM III, S4, Gen6)
• 1000 Vario

1. 1

   Verify if the fault is currently active or just stored in the history via the instrument panel multiple display.

2. 2

   Inspect the physical CAN bus wiring harness (G-Bus/transmission bus and V-Bus/valve bus) connecting to the A050 ECU for chafing, corrosion, or loose pins.

3. 3

   Verify the power supply (+UB) and ground connections at the A050 ECU separation points (e.g., X169 connector).

4. 4

   Use the FENDIAS diagnostic software or a 160-pin adapter box to run a direct test on the A050 ECU to determine if the module is failing to send/receive messages.

1. 1

   Clear the Fault Memory

   Call up the fault code on the instrument panel, then press buttons A, B, and C (or both arrow keys depending on the terminal) simultaneously. Note: Faults stored deep in the A050 ECU may require FENDIAS diagnostic software to clear completely.

2. 2

   Perform EOL Programming

   Connect the tractor to the FENDIAS diagnostic tool and re-flash/re-program the A050 Basic Control Unit to restore bus communication parameters.

3. 3

   Module Repair/Replacement

   If EOL programming fails or the ECU has suffered an internal hardware failure (such as an EEPROM error), the A050 Basic Control Unit must be removed and either sent to a specialized agricultural electronics repair facility or replaced entirely.

4. 4

   Post-Installation

   If a new or remanufactured A050 ECU is installed, it must undergo EOL programming to sync with the tractor's immobilizer (A077) and Engine Control Unit (EDC).