Fendt 01.1.A1 – A050 / A002 / A051: CAN connection fault

The communication link between the tractor's basic/enhanced control unit and the engine control unit has been interrupted or failed. The Engine Control Unit (EDC) fails to report its status over the CAN bus network.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• Fendt 200 V/F/P Vario (207, 208, 209, 210, 211)
• Fendt 300 Vario COM III (312)
• Fendt 400 Vario COM III (411, 412, 413, 414, 415)
• Fendt 700 Vario COM III (712, 714, 716, 718)
• Fendt 800 Vario COM III (818, 820)
• Fendt 900 Vario COM III (916, 919, 920, 922, 924, 926, 927, 930, 933, 936)

1. 1

   Connect the Fendt SERDIA (Service Diagnostics) program to read the fault log and test the functioning of the CAN bus and EDC engine control.

2. 2

   Consult the 'Transmission bus' and 'EDC engine control' circuit diagrams (Sheet 5, Sheet 21, or Sheet 28). Check the physical wiring harness for breaks, corrosion, or loose pins between the A050/A002 module and the A051 module.

3. 3

   Verify that the immobilizer (A077) is successfully communicating with the engine control unit, as a mismatch in the vehicle serial number can shut down engine communication.

4. 4

   Verify that the engine type matches the entered tractor type. If a module was recently replaced, it may require EOL (End of Line) programming to load the correct engine data record.

1. 1

   Read and Clear

   Use the SERDIA tool to confirm the 01.1.A1 code. Check if it is an active or stored fault.

2. 2

   Inspect Harness

   Locate the A051 Engine Control Unit (usually mounted on the engine block, fuel-cooled, or near the right entrance step/battery case depending on the series) and the A050 Basic Control Unit. Disconnect the harness connectors (e.g., X1466, X1671, X1672) and inspect for moisture, bent pins, or corrosion.

3. 3

   Continuity Test

   Using a multimeter and the appropriate adapter cables (e.g., YELLOW/GREEN adapter boxes), measure the resistance of the CAN High and CAN Low lines between the A050 and A051 modules to isolate open or short circuits.

4. 4

   Repair Wiring

   If a wiring fault is found, repair the CAN bus lines or replace the affected harness section.

5. 5

   Module Testing/Replacement

   If the wiring is intact, the fault lies internally within either the A050 or A051 ECU. Send the suspected unit out for bench-testing/repair, or replace it with a new unit.

6. 6

   EOL Programming

   If the A050 or A051 ECU is replaced, you MUST perform EOL (End of Line) programming using SERDIA to flash the correct engine parameters and tractor serial number to the new module.