Massey Ferguson E521000.02 – Engine Control Unit (ECU): DEF Pump Control Issue (ECU)

Triggered when the DEF (Diesel Exhaust Fluid) pump temperature signal duty cycle falls into an invalid range (FMI 2) or failure range (FMI 8). It indicates that the engine control unit is detecting an abnormal signal, a speed deviation, or a lack of control over the DEF pump motor, preventing the Selective Catalytic Reduction (SCR) system from properly dosing DEF into the exhaust stream.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624

1. 1

   Inspect the wiring harness and connectors between the Engine ECU and the DEF pump/supply module for rub points, corrosion, or loose pins

2. 2

   Use a multimeter to check the DEF pump motor control signal for short circuits to ground, short circuits to a high source, or open circuits

3. 3

   Verify overall battery voltage and ground integrity, as low voltage during cranking or weak grounds can cause the ECU to log false logic faults

4. 4

   Use a diagnostic scan tool to monitor the DEF pump temperature signal duty cycle and pump motor speed to determine if the internal sensor/motor has failed

1. 1

   Preparation

   Turn off the tractor, remove the key, and disconnect the battery to ensure safety and prevent short circuits.

2. 2

   Locate the Pump

   Locate the DEF supply pump module (typically mounted near the DEF tank).

3. 3

   Disconnect Lines

   Carefully disconnect the electrical harness from the DEF pump. Disconnect the DEF fluid lines. Note: Have a clean catch pan ready, as DEF fluid will spill. Clean any spilled DEF immediately with warm water, as it is highly corrosive to metal.

4. 4

   Remove the Pump

   Unbolt the DEF pump module from its mounting bracket and remove it from the machine.

5. 5

   Install New Pump

   Mount the new DEF pump/dosing module and secure the bolts.

6. 6

   Reconnect

   Reconnect the DEF fluid lines (ensure they click into place securely) and plug in the electrical harness.

7. 7

   Filter Replacement

   It is highly recommended to replace the DEF filter (if separate) while the system is open to prevent debris from damaging the new pump.

8. 8

   Programming/Calibration

   Reconnect the battery. Important: Depending on the exact module version, the new Bosch DEF dosing module may need to be programmed or calibrated to the vehicle's ECU using an AGCO diagnostic tool.

9. 9

   Clear Codes and Test

   Clear the E521000.02 fault code from the ECU. Start the engine and allow it to reach operating temperature to verify the DEF system builds pressure and the code does not return.