Massey Ferguson 4376.05 – Engine ECU (EEM4): The DEF Reverse Flow Solenoid Valve Low Amps

The control module has detected an open circuit or abnormally high resistance in the electrical circuit for the DEF pump's reversing valve.

• 4710
• 7724S
• 5712SL
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 5613
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7616
• 7618
• 5608
• 4708
• 7619
• 7626
• 7726S
• 7624
• 4707
• 4709
• 5711SL
• 7614
• 7718S
• 5610
• 7620
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 5612
• 7622
• 7720
• Tier 4 (2015-2021)
• 5611
• 7715S
• 5609
• 7724
• 5710 SL
• 5711 SL
• 5712 SL
• 5713 SL
• 7714S
• 7719S

1. 1

   Inspect the wiring harness running from the Engine ECU to the DEF pump/dosing unit for chafed wires, breaks, or rodent damage.

2. 2

   Disconnect the main electrical connector at the DEF pump and inspect the pins for corrosion, pushed-out terminals, or moisture (DEF crystallization).

3. 3

   Using a multimeter, check the continuity of the reversing valve control wires from the ECU harness connector to the DEF pump connector to ensure there is no open circuit or short-to-ground.

4. 4

   Measure the resistance across the reversing valve solenoid pins directly on the DEF pump. An 'OL' (infinite resistance) or abnormally high ohm reading indicates the solenoid coil has failed open.

1. 1

   Turn off the tractor, remove the key, and disconnect the battery to prevent electrical shorts.

2. 2

   Thoroughly clean the area around the DEF pump to prevent dirt or debris from entering the DEF system.

3. 3

   Disconnect the electrical harness connector from the DEF pump.

4. 4

   Carefully disconnect the DEF fluid lines (suction, pressure, and backflow) and the engine coolant lines (which heat the pump).

   Be prepared to catch minor coolant and DEF spills.

5. 5

   Unbolt the DEF pump mounting hardware and remove the faulty dosing unit from the chassis.

6. 6

   Install the new DEF pump and torque the mounting bolts to OEM specifications.

7. 7

   Reconnect the coolant lines and DEF fluid lines, ensuring they click securely into place.

8. 8

   Reconnect the electrical harness.

9. 9

   Reconnect the battery and turn the ignition on.

   Use a diagnostic scan tool to clear the fault codes and run a 'DEF pressure build-up' or system prime test to verify operation and check for leaks.