Fendt B028 – Engine ECU: Motion Sensor / EDC Failure

This fault code indicates an issue within the Electronic Diesel Control (EDC) system, typically resulting in reduced engine power to prevent damage. Due to variations in documentation, the code may refer to a fault with either the Needle Movement Sensor (which provides injection timing feedback to the EDC) or the Boost Pressure Sensor (which measures intake manifold air pressure). Both conditions prevent the engine control unit from accurately regulating fuel delivery and engine performance.

• 900 Vario (COM III)
• 700 Vario
• Farmer 400
• General Vario Tractor models

1. 1

   Verify the fault code using the tractor's onboard diagnostic system to confirm B028 is active.

2. 2

   Inspect the wiring harness and connectors leading to the needle movement sensor (on the injector) and the boost pressure sensor (on the intake manifold) for damage, corrosion, or loose connections.

3. 3

   Check for other related EDC or CAN bus fault codes that could indicate a broader electrical issue.

4. 4

   If a Boost Pressure Sensor fault is suspected (intake precise failure): Check intake pipes between the turbo and engine for splits, leaks, or loose clamps. Inspect the sensor port for blockages from oily soot.

5. 5

   If a Needle Movement Sensor fault is suspected: Check the electrical connection to the specific fuel injector that houses the sensor.

1. 1

   Isolate faulty component

   Based on diagnostic checks, determine if the issue lies with the wiring, the boost pressure sensor, or the needle movement sensor.

2. 2

   Repair wiring

   Repair or replace any damaged wires or corroded connectors found during inspection. Clear fault codes and re-test the machine.

3. 3

   Replace Boost Pressure Sensor

   If the boost pressure sensor is determined to be faulty, locate it on the intake manifold, disconnect the electrical connector, unbolt the sensor, and install the new one.

4. 4

   Replace Needle Movement Sensor

   If the needle movement sensor is faulty, replace the entire fuel injector that houses the sensor. This may require specialized tools and bleeding of the fuel system.

5. 5

   Clear codes and test

   Clear all fault codes from the ECU's memory and operate the tractor under load to ensure full engine power is restored and the code does not return.