Fendt 1E.1.65 – A051 - ECU, engine control unit (EDC 7): Misfiring on cylinder 5

The engine control system has detected that the number of misfires on cylinder 5 has exceeded the allowed limit value, triggering a system reaction that may result in reduced engine power.

• 922 Vario COM III
• 924 Vario COM III
• 927 Vario COM III
• 930 Vario COM III
• 933 Vario COM III
• 936 Vario COM III
• Fendt 300 Vario (COM III)
• Fendt 400 Vario (COM III)
• Fendt 700 Vario (COM III)
• Fendt 800 Vario (COM III)
• Fendt 900 Vario (COM III)

1. 1

   Read and clear codes using FENDIAS or SERDIA diagnostic software to determine if the misfire is an active, hard fault or an intermittent issue.

2. 2

   Check for restricted fuel filters, poor fuel quality, or fuel starvation, which can destabilize injection pressure and cause intermittent misfires under load.

3. 3

   Inspect the wiring harness and electrical connectors leading to the cylinder 5 fuel injector for broken wires, short circuits, or loose connections.

4. 4

   Perform an engine compression test and a vacuum gauge test to rule out mechanical failures such as worn piston rings, head gasket faults, or intake/exhaust valve problems.

5. 5

   Inspect the EDC7 ECU for internal board corrosion or capacitor leakage, which can cause false misfire signals (rare).

1. 1

   Depressurize the System

   Ensure the engine is off and the high-pressure common rail fuel system is fully depressurized before opening any lines.

2. 2

   Remove Components

   Disconnect the electrical connector from the cylinder 5 injector. Loosen and remove the high-pressure fuel line connected to the injector.

3. 3

   Extract the Injector

   Remove the injector hold-down clamp/bracket and carefully extract the injector from the cylinder head.

4. 4

   Clean and Inspect

   Inspect the injector sleeve inside the cylinder head. Clean out any carbon deposits using a specialized brush or wood chips, ensuring no debris falls into the cylinder.

5. 5

   Install New Parts

   Install the new Bosch common rail injector along with a new injector sleeve and O-rings.

6. 6

   Reassemble

   Reconnect the high-pressure fuel line and the electrical connector. Torque all fittings to the OEM specifications.

7. 7

   Bleed and Program

   Bleed the fuel system. Connect the SERDIA diagnostic tool and perform EOL (End of Line) programming to input the new injector's calibration code into the A051 Engine Control Unit.

8. 8

   Test

   Start the engine and verify that the injection pressure difference across all cylinders is within the specified limit (less than 1MPa difference).