Fendt 1.2.E0 – A021 (EDC) / A002 (EST): Communication failure during CAN – Message between EDC Control Module and EST Comfort Module

The CAN bus network has experienced a timeout or communication failure between the engine's electronic control unit and the tractor's enhanced control/transmission module. This typically results in restricted operating possibilities, loss of enhanced features, and the tractor defaulting to a limited operating mode (e.g., only foot throttle available, engine torque reduced).

• 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
• Farmer 400 Vario Series: 409, 410, 411, 412
• Favorit 700 Vario Series: 711, 712, 714, 716
• 800 Vario Series: 815, 817, 818
• Favorit 900 Vario Series: 916, 920, 924, 926, 930
• COM III Vario Models: 300, 400, 700, 800, and 900 Vario (COM III)

1. 1

   Wiring & Harness Inspection: Check the physical CAN bus wiring between the A021 (EDC) and A002 (EST) modules. Look for chafed wires, broken connections, or corrosion at the connector pins.

2. 2

   Electric Diagram Verification: Consult the "EDC Control" and "Transmission - BUS" circuit diagrams to trace the CAN High and CAN Low lines.

3. 3

   Voltage & Ground Checks: Verify that both the A021 and A002 modules are receiving proper operating voltage (UB 15 from the ignition lock) and have clean grounds.

4. 4

   Diagnostic Tool Scan: Connect the FENDIAS or SERDIA diagnostic tool to check if the modules can be identified on the network. Look for accompanying EOL (End of Line) programming errors or EEPROM checksum faults.

1. 1

   Isolate the CAN Fault

   Disconnect the harness at the A021 and A002 modules. Use a multimeter to test the CAN lines for continuity, shorts to ground, or shorts to voltage.

2. 2

   Repair Wiring

   If a break or short is found in the "Transmission - BUS" harness, repair the wiring using appropriate OEM AMP Superseal or Minitimer connectors.

3. 3

   Software / EOL Programming

   If the wiring is intact but communication is still failing, the fault may be software-related. Use FENDIAS to perform an EOL (End of Line) reprogramming of the A002 and A021 modules.

4. 4

   Module Replacement

   If a module fails to accept programming, has an internal EEPROM failure, or outputs no CAN signal despite good power/ground, replace the faulty module (A021 or A002).

5. 5

   Calibration

   Any replaced module must be EOL programmed to match the specific tractor chassis and engine model.