Fendt 4.1.92 – Transmission Control Unit (TCU): Brake pedal left / right, data communication fault

The CAN bus network has lost communication with or is receiving invalid data from the left and right brake pedal position sensors, causing the automatic cruise control to become unavailable.

• 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
• Fendt Favorit 700 Vario series
• Fendt Favorit 900 Vario series

1. 1

   Check fuses F040 and F041 on the A013 printed circuit/fuse board to verify voltage supply for the CAN bus

2. 2

   Inspect electrical connectors at both the left and right brake pedals, and at the A001/A002 transmission modules, for corrosion

3. 3

   Inspect the CAN bus wiring harness between the brake pedals and the ECU for chafing, shorts to ground, or open circuits

4. 4

   Use the FENDIAS diagnostic program or the tractor's terminal to monitor live data from the brake pedal sensors for dead or intermittent signals

1. 1

   Preparation

   Safely park the tractor, turn off the ignition, and engage the parking brake.

2. 2

   Power Supply Verification

   Access the A013 fuse board and test fuses F040 and F041. Replace them if blown.

3. 3

   Harness & Connector Repair

   Disconnect the wiring harness at the brake pedal travel sensors. Clean the pins with electrical contact cleaner to remove any moisture or corrosion. Ensure the terminal pins are not bent or spread.

4. 4

   Sensor Replacement

   If the wiring and power supply are intact but the communication fault persists, the brake pedal travel sensor has likely failed internally. Unbolt the faulty sensor(s) from the pedal assembly and install the replacement part.

5. 5

   Clear Codes

   Reconnect the battery/ignition. Use the FENDIAS diagnostic tool or the in-cab terminal to clear the 4.1.92 fault code.

6. 6

   Test Drive

   Operate the tractor and verify that the automatic cruise control function has been restored and the fault code does not return.