Fendt 4.1.A1 – Transmission Control Unit: Turn angle is not reached within 2 seconds.

In the Fendt Vario transmission, the actuator unit rotates an actuator shaft to adjust the variable-displacement pump and motors, which controls the transmission ratio and direction. When the ignition is switched on, the actuator unit searches for a reference point (the approximate neutral point between forward and reverse). If the actuator motor is commanded to turn but fails to reach the specified angle within a 2-second window, this fault is triggered. The tractor will typically default to an emergency mode.

• 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
• 200 Vario (V, F, P series)
• 300 Vario (COM III)
• 400 Vario (Farmer 400, 409, 410, 411, 412, COM III)
• 700 Vario (Favorit 700, 711, 712, 714, 716, COM III)
• 800 Vario (815, 817, 818, COM III)
• 900 Vario (Favorit 900, 916, 920, 924, 926, 930, 936, COM III, S4)

1. 1

   Mechanical Verification (Emergency Mode Check): Engage the emergency control system and use the emergency socket wrench to manually rotate the actuator shaft. The slip clutch should measure between 2.5 Nm to 3.5 Nm (must be less than 5 Nm). If stiff, the issue is mechanical.

2. 2

   Electrical Supply Check: Check the power supply to the electric motor of the A009 Actuator Unit. Verify voltage is between 12 to 14 VDC. Under load, voltage drop must not exceed 1V. Check the ground connection (Pin 8).

3. 3

   Wiring and Connector Inspection: Inspect the wiring harness and connectors leading to the transmission actuator for moisture, corrosion, or damaged pins. Clean with contact spray if necessary.

1. 1

   Secure the Tractor

   Park on a level surface, turn off the engine, apply the parking brake, and relieve any hydraulic pressure.

2. 2

   Isolate the Fault

   Based on the diagnostic checks, determine if the actuator shaft is mechanically binding or if the A009 actuator unit has failed electrically.

3. 3

   Address Mechanical Binding (If Applicable)

   If the emergency manual adjustment was stiff (exceeding 5 Nm of resistance), the mechanical control housing or the actuator shaft itself must be dismantled, inspected for scoring/debris, cleaned, and reassembled or replaced.

4. 4

   Replace the Actuator Unit (If Applicable)

   If the mechanical linkage moves smoothly and electrical supply is verified, the A009 Actuator Unit is defective. Disconnect the electrical harness from the A009 unit. Unbolt and remove the faulty actuator unit from the transmission housing. Install the new A009 actuator unit and torque bolts to OEM specifications. Reconnect the electrical harness.

5. 5

   Calibration / Initialization

   Switch on the ignition. The new actuator unit (A009) will automatically search for the reference point (approximate neutral point). Start the engine. The actuator unit will then locate the precise neutral point between forward and reverse travel.

6. 6

   Clear Codes

   Use the tractor's terminal or the FENDIAS diagnostic tool to clear the stored 4.1.A1 fault code and test drive the tractor to ensure full transmission functionality is restored.