Fendt 1.2.C7 – EDC (Electronic Diesel Control) Control Module (A021) / Pump Control Unit (A020): A020 - Pump control unit (injection pump) (EDC) — Pump speed sensor fault (IWZ signal)

This fault code indicates a failure involving the internal pump speed/rotation angle sensor (known as the IWZ signal) inside the Bosch VP44 electronic injection pump. When the pump control unit (PSG) loses this signal, it cannot calculate the correct injection timing or volume, resulting in an immediate engine stall or a crank-no-start condition.

• 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
• Favorit 916 Vario
• Favorit 920 Vario
• Favorit 924 Vario
• Favorit 926 Vario
• Favorit 930 Vario
• Favorit 711 Vario
• Favorit 712 Vario
• Favorit 714 Vario
• Favorit 715 Vario
• Favorit 716 Vario
• Favorit 717 Vario
• Farmer 409 Vario
• Farmer 410 Vario
• Farmer 411 Vario
• Farmer 412 Vario
• 815 Vario
• 817 Vario
• 818 Vario

1. 1

   Check battery voltage during cranking (a severe voltage drop can cause the EDC to misread the sensor, triggering a false code)

2. 2

   Inspect the wiring harness and main electrical connector at the VP44 injection pump for corrosion, backed-out pins, or chafing

3. 3

   Check the fuel system for air intrusion and ensure the fuel supply pump is delivering adequate pressure to the VP44 pump

1. 1

   Test and Charge Batteries

   Load-test the tractor's batteries. If they are weak and voltage drops significantly during cranking, replace the batteries and clear the fault codes to see if the issue resolves.

2. 2

   Clean Connections

   Disconnect the main harness at the injection pump, clean the contacts with electrical contact cleaner, and ensure a tight fit.

3. 3

   Address Internal Pump Failure

   If the batteries and wiring are in good condition, the fault is internal to the Bosch VP44 injection pump (either the IWZ sensor itself or the PSG control module mounted on top of the pump has failed). The IWZ sensor is connected to the pump control unit via a flexible conductive ribbon cable inside the pump.

4. 4

   Remove the Injection Pump

   Following the Fendt workshop manual (Chapter 2710), lock the engine at top dead center (TDC), remove the injection pump gear, and dismount the VP44 injection pump.

5. 5

   Rebuild or Replace

   Because the IWZ sensor and PSG module are internal/integrated components, the pump must either be sent to a certified Bosch Diesel Service Center for a rebuild and calibration, or replaced entirely with a remanufactured unit.

6. 6

   Reinstall and Bleed

   Install the new/rebuilt pump, time the engine according to OEM specs, and bleed the fuel system of all air before attempting to start.