Fendt 1E.1.79 – A051 - ECU, engine control unit (EDC 7): Break in wiring of cylinder bank 1 injector valves

The engine control unit has detected an open circuit (cable break) in the electrical circuit supplying the fuel injectors for cylinder bank 1. To protect the engine and prevent unburnt fuel issues, the ECU initiates a Cylinder switch-off. The engine will run rough, misfire, and experience a severe loss of power.

• 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 300 Vario COM III (Models: 309, 310, 311, 312)
• FENDT 400 Vario COM III
• FENDT 700 Vario COM III
• FENDT 800 Vario COM III
• FENDT 900 Vario COM III (Models: 922, 924, 927, 930, 933, 936)

1. 1

   Visual Inspection: Inspect the engine wiring harness routing from the A051 (EDC 7) control unit to the cylinder head/injector bank 1. Look for obvious signs of chafing, heat damage, or rodent damage.

2. 2

   Connector Check: Disconnect the main harness connector at the cylinder head and at the EDC 7 module (Connector X1466). Check for loose pins, pushed-back terminals, corrosion, or moisture ingress.

3. 3

   Continuity/Resistance Testing: Using a multimeter, measure the resistance of the injector circuits for bank 1 from the EDC 7 harness connector to the injector connectors. You are looking for an open circuit (infinite resistance) which confirms the 'cable break'.

4. 4

   Injector Solenoid Test: While the harness is disconnected, measure the resistance across the pins of the bank 1 injectors themselves to rule out an internal open circuit within the injector solenoid.

1. 1

   Disconnect Power

   Turn off the ignition and disconnect the tractor's battery to prevent electrical spikes.

2. 2

   Isolate the Break

   Based on your continuity test, locate the exact point of the open circuit. If the break is external and accessible, you may be able to repair the wire using OEM-approved heat-shrink butt connectors.

3. 3

   Replace the Harness (If necessary)

   If the wiring harness is heavily degraded, oil-soaked, or the break is internal to the molded cylinder head pass-through, the injector wiring harness must be replaced.

4. 4

   Reassemble and Reconnect

   Plug all injector connectors and the main EDC 7 (X1466) connector back in. Ensure the harness is routed away from high-heat sources (like the exhaust manifold) and secured with zip ties to prevent future chafing.

5. 5

   Clear the Fault Code

   Reconnect the battery. The fault code (Internal FC: 009A) must be cleared from the A051 ECU memory using the Deutz SERDIA or FENDIAS diagnostic software. The engine will remain in cylinder shut-off mode until the error is successfully deleted.