Fendt 1.2.C8 – EDC (Electronic Diesel Control) Engine Control Module (A021): Injection volume is not precise

The system detects that the calculated injection volume is inaccurate, which is typically caused by faulty signals from the Needle Motion Sensor (B026) or the Intake Air Pressure / Boost Pressure Sensor (B028). When this fault is triggered, the engine will stall or stop running.

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1. 1

   Connect the FENDIAS diagnostic tool to record failure and ambient parameters, then delete the failure memory to see if the fault returns

2. 2

   Inspect the wiring and connectors for the Needle Motion Sensor (B026) and the Boost Pressure Sensor (B028) for disruptions, short circuits, or loose connections

3. 3

   Test the Needle Motion Sensor (B026) for signal amplitude (signal too low), missing pulses, too many impulses, or incorrect internal resistance

4. 4

   Check for disturbance pulses on the Needle Motion Sensor caused by mechanical failures (e.g., valve control, pistons) or a stuck injector needle

5. 5

   Check the fuel system thoroughly, ensuring the fuel tank is filled, the fuel lifting pump is operational, and inspecting for contaminated fuel filters, clogged lines, or air in the system

1. 1

   Clear and Verify

   Use FENDIAS to clear the code. Attempt to start the tractor. If the engine stops and the code returns, proceed to physical inspections.

2. 2

   Inspect Wiring

   Trace the wiring harness from the EDC Control Module (A021) to the Needle Motion Sensor (B026) and Boost Pressure Sensor (B028). Repair any broken wires or corroded pins.

3. 3

   Service the Fuel System

   Replace the fuel filter if it is contaminated. Bleed the fuel lines to ensure there is no air in the system, and verify the fuel lifting pump is operating correctly.

4. 4

   Test/Replace Sensors

   If wiring and fuel supply are good, test the Needle Motion Sensor (located on the injector nozzle for cylinder 1) and the Boost Pressure Sensor. Replace whichever sensor is failing the resistance/signal amplitude tests.

5. 5

   Inspect Injectors and Pump

   If the sensors are functioning properly, the issue may be a stuck injector needle or an internal failure within the injection pump itself. Replace the faulty injector or injection pump as necessary.