Fendt 1.2.C9 – EDC Control Module (Engine Control Unit - A021): Pump control unit (injection pump) (EDC) — Fault during self-diagnostic test (solenoid valve output stage)

The Electronic Diesel Control (EDC) system has detected an internal electrical failure within the injection pump's control unit during its startup self-diagnostic check. Specifically, the output stage that controls the high-pressure solenoid valve inside the pump is reporting a fault.

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1. 1

   Test battery and charging system — a severe voltage drop during engine cranking can cause the pump control unit's solenoid output stage to fail its self-diagnostic test

2. 2

   Inspect the EDC control circuit wiring harness and connectors between the Engine Control Unit (A021) and the Pump Control Unit (A020) for corrosion, loose pins, or chafing

3. 3

   Verify primary fuel supply pressure and the interior pressure of the pump to ensure the pump is not being starved of fuel (which causes internal overheating)

1. 1

   Verify Voltage

   Connect a multimeter to the battery and monitor voltage during engine cranking. If voltage drops below specification, replace the batteries and clear the fault codes.

2. 2

   Inspect Harness

   Disconnect the main plug at the VP44 injection pump. Clean the contacts with electrical contact cleaner and ensure the locking mechanism is tight upon reinstallation.

3. 3

   Replace/Remanufacture the Pump

   If battery voltage is strong and the wiring is intact, the solenoid valve output stage inside the Pump Control Unit (A020) has failed. Because the PSG (pump control unit) is integrated into the Bosch VP44 pump, remove and replace the entire injection pump assembly.

4. 4

   Installation

   Install the replacement or remanufactured VP44 injection pump. Ensure the engine is pinned at top dead center (TDC) and the pump gear is correctly timed according to the MAN D0836 engine service manual.

5. 5

   Bleed the Fuel System

   Prime the fuel system to remove all air before attempting to start the tractor.

6. 6

   Clear Codes

   Use FENDIAS or a compatible diagnostic tool to clear the 1.2.C9 fault code from the EDC module and verify normal operation.