Fendt 04.1.EC – A050 Basic Control Unit ECU: B055 - Engine speed setpoint ('foot throttle') rotary position sensor; combi-sensor.

The foot throttle (accelerator pedal) rotary position sensor has lost its calibration, or its values have drifted and changed beyond acceptable parameters, causing the Tractor Management System (TMS) and the Load Limit Control to be deactivated.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• 200 Vario series (V/F/P models)
• 300 Vario series (COM III)
• 400 Vario series
• 700 Vario series
• 800 Vario series
• 900 Vario series (COM III, S4, etc.)

1. 1

   Inspect the foot throttle pedal assembly for physical damage, debris, or mechanical binding that could prevent the pedal from returning to its resting position or reaching full travel.

2. 2

   Inspect the wiring harness and the 6-way connector at the B055 sensor for corrosion, pushed-out pins, or chafed wires that could cause voltage drops or drifted signal values.

3. 3

   Use a diagnostic tool (like FENDIAS) to monitor the live voltage/current values of the B055 combi-sensor as you slowly depress the pedal, looking for erratic jumps or dropouts in the signal.

4. 4

   Cycle the tractor's key off and perform a cold start to see if the TMS system restores functionality temporarily.

1. 1

   Access the Sensor

   Locate the B055 rotary position sensor mounted on the foot throttle pedal assembly inside the cab.

2. 2

   Replace the Sensor (if faulty)

   Disconnect the electrical harness. Remove the mounting hardware securing the sensor to the pedal pivot shaft. Install the new rotary position sensor and secure the hardware. Reconnect the wiring harness.

3. 3

   Perform Calibration

   Because the fault code specifically flags missing or drifted calibration, you must recalibrate the sensor after replacement (or if the original sensor simply lost its calibration).

4. 4

   Calibration Code

   Enter the Fendt onboard diagnostic/calibration menu and run Calibration Code 4005 (Foot throttle/accelerator pedal calibration). Follow the on-screen prompts to register the pedal's minimum and maximum travel positions.

5. 5

   Clear Codes and Test

   Clear the 04.1.EC fault code from the A050 ECU. Restart the tractor and verify that the TMS and Load Limit Control systems are active and functioning normally.