Fendt 4.1.41 – Transmission Control Unit (TRANSMISSION / Transmission Control Module): B011 - Engine speed Hall sensor 2 — Signal fault

The system has lost the signal from the second engine speed sensor (B011). Both sensors (B010 and B011) are required to provide an identical, plausible signal curve. If the B011 sensor fails or its signal is interrupted, the system detects a signal failure or plausibility error, restricting the tractor to "Auxiliary Operation" (Emergency mode) with reduced power.

• 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
• Farmer 400 Vario
• Favorit 700 Vario
• Favorit 800 Vario
• 815 Vario
• 817 Vario
• 818 Vario
• Favorit 900 Vario
• 300 Vario COM III
• 400 Vario COM III
• 700 Vario COM III
• 800 Vario COM III
• 900 Vario COM III

1. 1

   Verify the 12V power supply to the sensor circuit, specifically checking fuse A013.

2. 2

   Inspect the wiring harness and the B011 sensor's electrical connector (located at the top left rear on the engine) for corrosion, chafing, or loose pins.

3. 3

   Using a diagnostic tool (like FENDIAS), monitor the live data for both B010 (Sensor 1) and B011 (Sensor 2). Both must provide an identical speed curve. If B010 is reading correctly but B011 is flatlined or erratic, the fault is isolated to the B011 circuit or sensor.

1. 1

   Turn off the engine, remove the key, and engage the parking brake.

   Ensure the machine is safely secured before beginning work.

2. 2

   Open the engine cowling and locate the B011 Engine speed Hall-effect sensor.

   The sensor is located at the top left rear of the engine block.

3. 3

   Disconnect the electrical connector from the B011 sensor.

   Prepare the sensor for electrical testing.

4. 4

   Verify the wiring harness voltage and continuity.

   Using a multimeter, verify that the wiring harness is delivering the correct voltage (12V) and that there are no open circuits between the sensor connector and the Transmission Control Module.

5. 5

   Remove the B011 sensor.

   If the wiring and fuse A013 are intact, remove the retaining fastener holding the B011 sensor in place and pull the sensor out of the engine block.

6. 6

   Install the replacement engine speed sensor.

   Tighten the fastener to the manufacturer's specification.

7. 7

   Reconnect the electrical harness.

   Ensure the connector clicks securely into place.

8. 8

   Clear the fault code.

   Connect a diagnostic tool to clear the 4.1.41 fault code from the Transmission Control Module.

9. 9

   Test the tractor.

   Start the tractor and verify that it successfully exits "Auxiliary Operation" (emergency mode) and that no warning lights remain on the dash.