Fendt 1.2.B7 – EDC (Electronic Diesel Control) Module / Engine Control Unit (A021): A020, B025 - Pump control unit (injection pump), engine speed sensor (EDC) — Fault in speed signal to pump control unit

This code indicates a signal processing failure within the injection pump. The engine speed sensor (B025) is either sending a statically/dynamically implausible signal, or the pump control unit (A020) is failing to process the speed signal correctly. The engine goes into a restricted operating mode, resulting in reduced engine speed and a 25-40% reduction in full power flow (maximum speed limited to 1800 RPM).

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1. 1

   Inspect the B025 EDC speed sensor for physical damage or metallic chips on the magnetic tip, which can cause an erratic or wrong signal.

2. 2

   Verify that the distance from the speed sensor to the flywheel is within specification.

3. 3

   Inspect the wiring harness between the B025 speed sensor (Connector X172: Pin 1 Earth, Pin 2 Signal) and the A020 Pump Control Unit for wire disruptions or short circuits.

4. 4

   Check the voltage supply and earth to the VP44 injection pump (A020) under load.

5. 5

   Connect the FENDIAS diagnostic tool, record the failure and ambient parameters, clear the fault memory, and run the tractor to see if the fault returns.

1. 1

   Clean and Adjust

   Remove the B025 EDC speed sensor. Clean any metallic debris from the sensor tip. Reinstall and ensure it is seated at the correct distance to the flywheel.

2. 2

   Repair Wiring

   If the wiring harness tests show high resistance, a short to ground, or a break, repair or replace the affected section of the EDC control circuit harness.

3. 3

   Clear and Retest

   Use the FENDIAS system to delete the failure code memory. Keep the engine at a standstill for at least 5 seconds between start trials, then check again with FENDIAS.

4. 4

   Replace Injection Pump

   If the sensor and wiring are verified to be in good working order and the fault persists, the internal signal processor of the pump control unit has failed. Replace the Injection Pump.