Fendt 1.2.85 (MAN EDC) – EDC Control Module: B028 - Boost pressure sensor (EDC) / Sensor Intake pressure LDF — Signal fault

This code indicates that the engine management system has detected a signal failure, an open circuit (break in wiring), or a short circuit in the boost pressure sensor circuit. Because the ECU cannot accurately read the intake manifold charge pressure, it triggers a protective "restricted power" or "reduced power" mode to prevent engine damage.

• 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 409
• Farmer 410
• Farmer 411
• Farmer 412
• Favorit 711
• Favorit 712
• Favorit 714
• Favorit 716
• Favorit 717
• Favorit 718
• Favorit 815
• Favorit 817
• Favorit 818
• Favorit 820
• Favorit 916
• Favorit 920
• Favorit 924
• Favorit 926
• Favorit 930 Vario

1. 1

   Inspect the B028 sensor's 4-pin electrical connector and wiring harness for corrosion, chafing, or breaks.

2. 2

   Verify the reference voltage supply to the sensor from the EDC/EMR2 module (should read a steady 5 VDC).

3. 3

   Back-probe the sensor signal wire using a multimeter (expected measurement is 2.70 - 3.00 V at 2000 mbar of intake pressure).

4. 4

   Check the intercooler, turbocharger piping, and intake manifold for physical boost leaks (cracks, loose clamps) that could cause actual pressure to fall outside the setpoint range.

1. 1

   Preparation

   Turn off the tractor ignition and disconnect the negative battery terminal to prevent electrical spikes.

2. 2

   Locate the Sensor

   Locate the B028 boost pressure sensor, which is mounted directly on the intake manifold or charge air pipe.

3. 3

   Removal

   Depress the locking tab and disconnect the 4-pin electrical connector from the sensor. Remove the retaining fastener(s) securing the sensor to the manifold. Carefully pull the old sensor out of its mounting port.

4. 4

   Installation

   Clean the mounting port on the intake manifold to ensure a proper seal. Insert the new boost pressure sensor and tighten the retaining fastener to the manufacturer's specified torque. Reconnect the 4-pin electrical connector until it clicks into place.

5. 5

   Clear Codes & Test

   Reconnect the battery and turn the ignition ON. Use the SERDIA diagnostic tool (or the tractor's onboard terminal) to clear the stored 1.2.85 fault code. Start the engine and test drive the tractor under load to verify that full power is restored and the fault code does not return.