Fendt 4.1.A2 – Transmission Control Unit: CAN-bus actuation fault related to the A009 - Actuator unit

A faulty CAN bus connection or communication error is preventing the control unit from properly actuating the transmission adjustment device. The tractor will typically lose enhanced control features, but continuation in emergency mode is possible.

• 411 Vario COM III
• 412 Vario COM III
• 413 Vario COM III
• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
• 716 Vario COM III
• 718 Vario COM III
• 818 Vario COM III
• 820 Vario COM III
• Farmer 400 / 400 Vario (COM III): 409, 410, 411, 412, 413, 414, 415
• Favorit 700 / 700 Vario (COM III / SCR): 711, 712, 714, 715, 716, 717, 718, 720, 722, 724
• Fendt 800 Vario (COM III): 815, 817, 818
• Favorit 900 / 900 Vario (COM III / S4): 916, 920, 922, 924, 926, 927, 928, 930, 933, 936, 939
• Fendt 300 Vario (COM III): 309, 310, 311, 312, 313
• Fendt 500 Vario: 512, 513
• Fendt 1000 Vario: 1038, 1042, 1046, 1050

1. 1

   Engage the emergency control system and verify the mechanical adjustment device (actuator unit) moves smoothly without binding.

2. 2

   Inspect the CAN bus wiring harness between the A009 actuator unit and the transmission control unit for breaks, chafing, or short circuits.

3. 3

   Measure the resistance across the CAN bus pins at the separation point (target value is approximately 60 Ohms to confirm terminating resistors are intact).

4. 4

   Use the FENDIAS diagnostic program to read live data and confirm if CAN communication is completely passive or intermittent.

1. 1

   Secure tractor

   Turn the ignition OFF and ensure the tractor is safely secured with the hand brake applied.

2. 2

   Locate actuator

   Locate the A009 transmission actuator unit on the Vario transmission block.

3. 3

   Disconnect harness

   Disconnect the electrical harness connector from the A009 actuator unit.

4. 4

   Remove hardware

   Remove the mounting hardware securing the actuator unit to the transmission housing.

5. 5

   Remove actuator

   Carefully remove the old actuator unit, ensuring no dirt or debris enters the transmission housing.

6. 6

   Install new actuator

   Install the new A009 actuator unit and torque the mounting hardware to OEM specifications.

7. 7

   Reconnect harness

   Reconnect the CAN bus electrical harness.

8. 8

   Calibrate actuator

   Turn the ignition ON. Use the FENDIAS terminal to perform an EOL (End of Line) reprogramming or calibration so the ECU can learn the initial reference (zero position) of the new actuator.

9. 9

   Test drive

   Clear the stored fault codes and test drive the tractor to ensure full transmission control is restored and the tractor exits emergency mode.