Fendt 1.2.99 – A021 / A020: Engine stop via power monitor within EDC control module

This code indicates that the engine control system has triggered an engine shutdown due to an irregularity detected by the internal voltage/power monitoring circuit within the EDC (Electronic Diesel Control) module. The primary consequence of this fault is an immediate engine stop or severely reduced power.

• 409 Vario
• 410 Vario
• 411 Vario
• 412 Vario
• 711 Vario
• 712 Vario
• 714 Vario
• 715 Vario
• 716 Vario
• 717 Vario
• 718 Vario
• 916 Vario
• 920 Vario
• 924 Vario
• 926 Vario
• 930 Vario
• Farmer 400 series (409, 410, 411, 412)
• Favorit 700 series (711, 712, 714, 715, 716, 717)
• Favorit 900 series (916, 920, 924, 926, 930)
• 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

   Test battery voltage and ensure a stable power supply to the EDC Control Module (A021), checking for voltage drops during cranking and operation.

2. 2

   Check the power supply and fuses for the CAN bus circuit board (specifically on fuse board A013) and inspect the main EDC power relay to ensure contacts are closing properly.

3. 3

   Inspect the wiring harness between the EDC Control Module (A021) and the Pump Control Unit (A020) for chafing, corrosion, or loose pins (specifically check connectors X047 and X048).

4. 4

   Connect the FENDIAS diagnostic tool to monitor live voltage data at the EDC and check for secondary CAN-bus communication faults (such as 1.1.B0 or 1.2.B1).

1. 1

   Resolve Power Supply Issues

   If the diagnostic checks reveal low voltage or a faulty ground, clean all battery terminals, chassis grounds, and the specific grounding points for the A021 EDC module. Replace any blown fuses or sticking relays on the A013 board.

2. 2

   Repair Wiring

   If a short or open circuit is found between the A021 and A020 modules, repair the wiring harness using OEM AMP Superseal or Minitimer connectors.

3. 3

   Address the Engine Stop Solenoid

   Verify the function of the engine stop solenoid valve, as voltage irregularities here can trigger the power monitor shutdown.

4. 4

   Module Replacement (If Necessary)

   If the wiring, relays, and power supply are perfectly intact but the EDC continues to trigger a voltage monitor shutdown, the internal power monitor within the A021 EDC Control Module has likely failed. The A021 module will need to be replaced and EOL (End of Line) reprogrammed.

5. 5

   Injection Pump Replacement (Worst Case)

   If the fault is accompanied by injection volume errors or pump control autodiagnostic failures (e.g., code 1.2.C9), the A020 Pump Control Unit (integrated into the VP44 injection pump) is faulty, requiring replacement of the injection pump.