Fendt 1.2.B3 – Engine Control Unit (EDC): Interrupted power supply or supply failure to the pump control unit (injection pump)

A loss of electrical power to the engine's fuel injection control system. As a direct consequence, the engine will stall and will not start, triggering an 'Engine Stop' condition.

• 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
• 300 Vario series (COM III)
• 400 Vario series (409, 410, 411, 412)
• 700 Vario series (711, 712, 714, 715, 716, 717)
• 800 Vario series (815, 817, 818)
• 900 Vario series (916, 920, 924, 926, 930)

1. 1

   Verify the Fault: Confirm the active 1.2.B3 code on the tractor's terminal.

2. 2

   Battery & Voltage Check: Check the main batteries and ensure the system voltage is within the operating range (typically 8V to 18V) during cranking.

3. 3

   Circuit Diagram Verification: Consult the 'EDC control' circuit diagram (Chapter 2000 Reg.B) to identify the specific power supply pins for the A020/A051 module.

4. 4

   Harness Inspection: Inspect the wiring harness connecting the central electrics/fuse board to the EDC for chafing, breaks, or loose connections.

1. 1

   Power Down

   Turn off the ignition and disconnect the tractor's battery to prevent electrical shorts during testing.

2. 2

   Access the ECU

   Locate the A051 (EDC 7) or A020 pump control unit.

3. 3

   Test Power Supply

   Disconnect the main harness from the ECU. Using a multimeter, test the power supply pins (referenced in the EDC control circuit diagram) for continuity and proper voltage.

4. 4

   Inspect Fuses/Relays

   Check the microfuses and relays on the main circuit board (A013) that supply power to the engine control unit. Replace any blown fuses.

5. 5

   Repair Wiring

   If a break or short is found in the power supply line, repair the wiring harness or replace the damaged cable section.

6. 6

   Reassemble and Clear Codes

   Reconnect the ECU and battery. Use FENDIAS or SERDIA diagnostic software to clear the fault code from the A050 (basic control unit) and A051 (engine control unit) memory.

7. 7

   Test Run

   Attempt to start the engine to verify the power supply has been restored and the code does not return.