Fendt 1.2.C1 – Engine Control Unit (A051 / Bosch EDC 7): A051 - ECU, engine control unit (EDC 7). CAN bus times out with at least one sent message.

Communication failure where the engine control unit is not receiving expected CAN bus messages within the required timeframe, resulting in a timeout.

• 411 Vario COM III
• 412 Vario COM III
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• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
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• 919 Vario COM III
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• 927 Vario COM III
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• 936 Vario COM III

1. 1

   Read and Confirm Codes: Connect the AGCO 2x4 CANUSB Diagnostic Tool and use FENDIAS or SERDIA software to confirm the active fault (often associated with SERDIA FC:0083).

2. 2

   Wiring and Harness Inspection: Inspect the wiring harness connecting the A051 Engine ECU to the A002 Enhanced Control ECU for chafed wires, broken lines, or short circuits.

3. 3

   Check Connectors: Inspect the 68-pole connector at the EDC 7 unit for corrosion, pushed-back pins, or moisture ingress.

4. 4

   Test Emergency Operation: Verify if the tractor can still be driven using the foot throttle pedal.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the battery via the battery disconnect relay (K064) to prevent electrical spikes.

2. 2

   Repair Wiring

   If a break or short is found in the CAN bus wiring during diagnostics, repair the affected section of the harness or replace the specific adapter cable.

3. 3

   ECU Replacement/Repair

   If the wiring tests perfectly but the CAN timeout persists, the CAN transceiver inside the Bosch EDC 7 unit has likely failed. Remove the A051 ECU and send the Bosch EDC7UC31 unit to a specialized mechatronics repair facility or replace it with a new OEM unit.

4. 4

   Reassembly

   Reconnect the 68-pole harness to the ECU and restore battery power.

5. 5

   Software Calibration

   If a new A051 ECU is installed, it must be programmed with the correct EOL (End of Line) data record and engine parameters using FENDIAS/SERDIA so the engine model matches the tractor model.

6. 6

   Clear Faults

   Use the diagnostic software to delete the 1.2.C1 fault code from the memory. Do not clear the memory until the physical repair is complete.

7. 7

   Test Drive

   Operate the tractor to ensure full TMS (Tractor Management System) functionality has returned and the engine responds correctly to both hand and foot throttles.