Massey Ferguson E521000.08 – Engine Control Unit (ECU): DEF Pump Control Issue (ECU)

DEF pump temperature signal duty cycle in failure range or an AdBlue™ or DEF module temperature Fault with pump temperature signal. The controller is receiving an invalid, out-of-range, or missing temperature signal from the sensor integrated into the DEF pump.

• 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 module for open circuits, shorts to ground, or corrosion that could distort the temperature signal.

2. 2

   Test the DEF heater main relay for proper operation and ensure it is not shorted to a +12V source (often accompanied by codes E521001.03 or E521001.31).

3. 3

   Verify the DEF pump temperature sensor output signal using a diagnostic tool such as WinEEM3s or WinEEM4.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the battery to prevent electrical shorts during the repair.

2. 2

   Inspect/Repair Harness

   If the diagnostic checks reveal damaged wiring or corroded pins at the DEF pump connector or ECU, repair or replace the affected harness section.

3. 3

   Replace the DEF Pump Module

   If the wiring is intact and the relay is functioning, the internal temperature sensor of the DEF pump has failed. Because the sensor is integrated, the entire DEF pump/supply module must be replaced.

4. 4

   Reassemble and Prime

   Install the new DEF pump, reconnect the fluid lines, and plug in the electrical harness.

5. 5

   Clear Codes

   Reconnect the battery and use the AGCO WinEEM diagnostic service tool to clear the E521000.08 fault code and run a DEF system test to prime the pump and verify the temperature signal is now reading correctly.