Fendt 1E.1.64 – A051 - ECU, engine control unit (EDC 7): Misfiring on cylinder 4

The engine control unit has detected a misfire event on cylinder 4. The ECU monitors the rotational speed of the crankshaft (via the B088 crankshaft speed sensor) and camshaft (via the B085 camshaft speed sensor). If it detects a momentary drop in rotational acceleration during cylinder 4's power stroke, it logs this misfire code.

• 309 Vario COM III
• 310 Vario COM III
• 311 Vario COM III
• 312 Vario COM III
• 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 400 Vario COM III
• Fendt 700 Vario COM III
• Fendt 800 Vario COM III

1. 1

   Read the fault log using the SERDIA diagnostic tool to check for accompanying electrical faults, such as injector short circuits or open circuits.

2. 2

   Perform an actuator function test (injector cut-out test) using SERDIA. Disable cylinder 4 to see if the engine RPM drops; if there is no change, cylinder 4 is confirmed dead.

3. 3

   Inspect the wiring harness from the A051 (EDC 7) ECU to the cylinder 4 fuel injector for chafing, breaks, or short circuits.

4. 4

   Run an electronic compression test using the SERDIA software (Note: running this test will temporarily deactivate rail pressure monitoring and may trigger FC:00AF, which is normal).

5. 5

   If the electrical circuit is intact, perform mechanical checks for a faulty fuel injector, incorrect valve clearance, or low cylinder compression.

1. 1

   Isolate the Cause

   Based on the diagnostic checks, determine if the issue is electrical (wiring/ECU), fuel-related (injector), or mechanical (valves/rings).

2. 2

   Repair Wiring

   If a break or short is found in the injector harness, repair or replace the affected wiring section between the injector and the A051 ECU.

3. 3

   Replace Fuel Injector

   If the wiring and compression are good, the cylinder 4 fuel injector is likely clogged or mechanically failed. Depressurize the Deutz Common Rail (DCR) system, remove the high-pressure line, and replace the cylinder 4 injector.

4. 4

   Clear Fault Codes

   Once the physical repair is completed, connect the SERDIA diagnostic tool and delete the error code (FC:0029) from the A051 ECU memory.

5. 5

   Test Run

   Run the engine and monitor the "Measured values graphics" in SERDIA to ensure smooth rotational speed and verify the misfire does not return.