Fendt 4.1.A2 – Transmission Control Unit: CAN-bus actuation fault

The communication network (CAN bus) has lost contact with or is receiving invalid data from the transmission actuator unit, preventing the electronic adjustment of the transmission ratio.

• 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
• 309 Vario
• 310 Vario
• 311 Vario
• 312 Vario
• 413 Vario
• 414 Vario
• 415 Vario
• 815 Vario
• 817 Vario
• 818 Vario
• 820 Vario
• 922 Vario
• 927 Vario
• 933 Vario
• 936 Vario
• 939 Vario
• 1038 Vario
• 1042 Vario
• 1046 Vario
• 1050 Vario

1. 1

   Engage the emergency control system and manually check the ease of movement of the transmission adjustment device (actuator shaft) to rule out mechanical binding.

2. 2

   Verify the voltage supply to the CAN-Bus by checking fuse board A013, specifically inspecting fuses F040 and F041.

3. 3

   Test the CAN-BUS lines between the main ECU and the A009 actuator unit for continuity, shorts to ground, or damaged pins.

4. 4

   Inspect the physical connection between the A009 actuator unit and the transmission actuator shaft to ensure it has not vibrated loose or sheared.

1. 1

   Enter Emergency Mode

   To move the tractor into a workshop, use the emergency manual actuator shaft control from the cab. The transmission will be automatically locked to a maximum speed of approx. 30 km/h.

2. 2

   Inspect and Repair Wiring

   If fuses F040/F041 are blown, trace the CAN wiring harness to the transmission for chafing or shorts. Repair any broken wires in the CAN-High or CAN-Low lines leading to the A009 actuator.

3. 3

   Remove the Actuator Unit

   If the wiring and power supply are good, the A009 actuator unit itself has likely failed internally. Remove the right rear wheel and panel to access the actuator unit on the right side of the transmission housing.

4. 4

   Replace the Actuator Unit

   Unbolt the faulty A009 unit from the control housing and disconnect the electrical harness. Install the replacement actuator unit and ensure the connecting rod/actuator shaft is properly seated.

5. 5

   Initialization / Calibration

   Turn the ignition ON. The new A009 actuator unit must automatically search for and locate its reference point (the precise neutral point between forward and reverse travel). Do not start the engine until this initialization sweep is complete.

6. 6

   Clear Codes

   Connect the FENDIAS diagnostic tool to clear the 4.1.A2 fault code and test drive the tractor to ensure full automatic transmission adjustment is restored.