Fendt 1.2.3A – A051 - ECU, Engine Control Unit: Misfiring

The engine control unit has detected a cylinder misfire. This can be triggered by a lack of fuel pressure, a faulty fuel dispensing unit, damaged injector wiring, internal mechanical engine failure (valves/pistons), or an internal hardware fault within the engine control unit itself.

• 411 Vario COM III
• 412 Vario COM III
• 413 Vario COM III
• 414 Vario COM III
• 415 Vario COM III
• 712 Vario COM III
• 714 Vario COM III
• 716 Vario COM III
• 718 Vario COM III
• 818 Vario COM III
• 820 Vario COM III
• Fendt 200 Vario V / F / P
• Fendt 300 Vario COM III (309, 310, 311, 312)
• Fendt 400 Vario COM III (411, 412, 413, 414, 415)
• Fendt 700 Vario COM III (712, 714, 716, 718)
• Fendt 800 Vario COM III (818, 820 Vario greentec)
• Fendt 900 Vario COM III (919, 922, 924, 925, 927, 930, 933, 936)

1. 1

   Read the ECU Directly: Connect the SERDIA (Deutz) diagnostic software or FENDIAS to the X810 diagnostic socket. Verify the exact misfire code (FC:002F) in the A051 memory.

2. 2

   Electrical/Wiring Check: Check the injector cabling and the wiring harness leading to the A051 ECU for short circuits or cable breaks.

3. 3

   Fuel System Check: Check the fuel return system and dispensing unit (Y091). Measure the return pressure using a pressure gauge (target pressure: 0.2-0.5 bar) and compare target vs. actual rail pressures using SERDIA.

4. 4

   Mechanical Engine Check: If the fuel system and wiring are intact, perform a compression test and a vacuum gauge test to check for internal mechanical damage to the valves or pistons.

5. 5

   ECU Reset Test: Reset the ECU by switching the ignition off, waiting until the ECU has completely shut down, and switching the ignition back on to see if the error is a hard (active) fault.

1. 1

   Resolve the Root Cause

   Based on the diagnostics, repair or replace the damaged component. This may involve replacing a faulty fuel injector, repairing a broken wiring harness, fixing mechanical engine damage, or replacing the A051 Engine ECU if it has suffered an internal hardware failure.

2. 2

   Clear the Instrument Panel

   Press buttons A, B, and C simultaneously on the tractor's control panel to delete the fault codes from the A007 Instrument Panel memory.

3. 3

   Clear the Engine ECU

   Canceling the fault on the tractor display does not remove it from the engine control unit. You must use the SERDIA diagnostic software to interface with the A051 ECU and execute the "delete error" command for FC:002F.

4. 4

   EOL Programming (If ECU is replaced)

   If the A051 ECU was replaced, you must perform EOL (End of Line) programming. Installing a blank or incorrectly programmed ECU will trigger a secondary fault (1.1.A0: Wrong engine control unit / wrong EOL programming).

5. 5

   Test Drive

   Cycle the ignition and run the tractor under load to ensure the misfire condition is resolved and the code does not return.