Fendt 04.1.22 – Gearbox / Transmission Control System ECU: Throttle pedal resolution potentiometer faulty, Signal fault.

The B055 foot throttle sensor (accelerator pedal) consists of redundant potentiometers that send an analog voltage signal to the control unit to communicate the driver's torque/load request. When this signal fails or is out of range, the tractor registers a signal fault and automatically switches off the Tractor Management System (TMS). The tractor may be forced into an emergency or restricted operation mode.

• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III)
• Fendt 800 Vario (COM III)
• Fendt 900 Vario (COM III)

1. 1

   Check the B055 Foot Throttle Sensor Wiring: Inspect the wiring harness and connectors between the foot throttle sensor and the ECU for damaged wires, loose connections, or bent pins.

2. 2

   Verify Power Supply: The potentiometer requires a reference voltage. Depending on the specific Vario model, check for a steady 5.0 VDC or 8.5 VDC supply at the sensor connector (e.g., Pin 2 and Pin 5 on the B055 sensor).

3. 3

   Test the Potentiometer: Measure the resistance/continuity of the potentiometer as the pedal is depressed. The resistance should change smoothly without dropping out or spiking.

4. 4

   Check Calibration: Sometimes the EEPROM checksum is incorrect or the pedal has lost its calibration parameters. Attempt to recalibrate the throttle pedal via the tractor's terminal before replacing hard parts.

1. 1

   Preparation

   Turn off the tractor ignition, apply the handbrake, and ensure the machine is secure.

2. 2

   Access the Sensor

   Locate the B055 foot throttle sensor assembly at the base of the accelerator pedal.

3. 3

   Disconnect

   Unplug the electrical connector from the faulty throttle pedal potentiometer.

4. 4

   Remove

   Unbolt and remove the faulty potentiometer from the pedal shaft.

5. 5

   Install

   Mount the replacement potentiometer onto the pedal shaft and secure the hardware.

6. 6

   Reconnect

   Plug the electrical connector back into the new sensor.

7. 7

   Calibrate

   Turn the ignition ON. You must calibrate the new sensor to compensate for mechanical and electrical tolerances. Use the tractor's terminal or FENDIAS diagnostic software to perform the pedal calibration procedure so the ECU can learn the new base signal voltage.

8. 8

   Clear Codes

   Clear the stored 04.1.22 fault code and test drive the tractor to ensure the TMS function is restored.