Fendt 1.2.C4 – EDC Control Module (A021): A020 - Pump control unit (injection pump) (EDC) — Fault in CAN communication to pump control unit

The engine control system loses communication with the injection pump's integrated controller. As a safety precaution, the system enters a restricted operating mode, and the engine defaults to running at a constant idle of 720 RPM.

• 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
• Favorit 700 series
• Favorit 900 series (specifically chassis number 23/3001 and up)
• Vario COM III series (300, 400, 700, 800, and 900 Vario)

1. 1

   Verify that the Pump Control Unit (A020) is receiving proper operating voltage and has a solid ground connection, as power loss causes a CAN timeout.

2. 2

   Inspect the CAN Bus wiring harness between the EDC Control Module (A021) and the Pump Control Unit (A020) for chafed wires, breaks, or short circuits on the CAN-High and CAN-Low lines.

3. 3

   Disconnect the plugs at both the EDC (A021) and the VP44 injection pump (A020) and inspect for corrosion, moisture, or pushed-back pins.

4. 4

   Check for related fault codes like 1.2.C3 (CAN message fault during engine start) or 1.2.C5 (Fault in engine stop via solenoid) to confirm localized electrical issues at the pump.

1. 1

   Disconnect batteries

   Disconnect the tractor's batteries before servicing the EDC system to prevent electrical spikes.

2. 2

   Access injection pump

   Access the left side of the engine (under the bonnet) to locate the VP44 injection pump and its wiring harness.

3. 3

   Test CAN wiring

   Perform a continuity test on the CAN communication wires from the EDC module to the pump. Repair any damaged wiring or replace the harness section if necessary.

4. 4

   Diagnose internal fault

   If the wiring, power, and ground are all verified as fully functional, the fault lies internally within the Pump Control Unit (A020).

5. 5

   Remove injection pump

   Because the A020 module is integrated into the Bosch VP44 injection pump, the entire injection pump must be removed.

6. 6

   Install new pump

   Install a new or professionally remanufactured Bosch VP44 injection pump.

7. 7

   Bleed fuel system

   Bleed the fuel system thoroughly to remove all air.

8. 8

   Clear fault codes

   Reconnect the batteries, start the tractor, and use the FENDIAS diagnostic tool to clear the fault code memory.