Massey Ferguson 4376.03 – ECU: DEF Reverse Flow Solenoid Valve High Voltage

The control module has detected that the voltage on the DEF Reverse Flow Solenoid Valve circuit is above normal, shorted to a high power source, or has an open circuit.

• 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
• MF 4707
• MF 4708
• MF 4709
• MF 4710
• MF 5608
• MF 5609
• MF 5610
• MF 5611
• MF 5612
• MF 5613
• MF 5710 SL
• MF 5711 SL
• MF 5712 SL
• MF 5713 SL
• MF 7614
• MF 7615
• MF 7616
• MF 7618
• MF 7619
• MF 7620
• MF 7622
• MF 7624
• MF 7626
• MF 7714
• MF 7715
• MF 7716
• MF 7716S
• MF 7718
• MF 7718S
• MF 7719
• MF 7720
• MF 7720S
• MF 7722
• MF 7722S
• MF 7724
• MF 7724S
• MF 7726
• MF 7726S

1. 1

   Visually inspect the DEF Supply Module main electrical connector for pushed-out pins, corrosion, or DEF fluid intrusion.

2. 2

   Disconnect the harness from the DEF pump and ECU, and measure the resistance of the reverse flow valve control wires to check for an open circuit or short to battery voltage.

3. 3

   Measure the resistance across the reverse flow solenoid pins directly on the DEF pump module to check for an open coil (internal solenoid failure).

4. 4

   Use the AGCO SCR Diagnostic Tool Kit or a compatible scanner to manually command the DEF reverse flow valve and monitor the voltage/current response.

1. 1

   Power Down

   Turn off the ignition and disconnect the tractor's battery to prevent electrical shorts.

2. 2

   Harness Repair

   If the diagnostic checks revealed a broken wire or short in the chassis harness, splice and repair the affected wiring using weather-sealed connectors, or replace the harness section.

3. 3

   DEF Pump Replacement

   If the solenoid has failed, relieve any residual pressure in the DEF lines. Disconnect the DEF inlet, outlet, and backflow fluid lines from the DEF Supply Module. Disconnect the main electrical harness. Unbolt the DEF Supply Module from its mounting bracket. Install the new DEF Supply Module and torque the mounting bolts to OEM spec. Reconnect the fluid lines, ensuring the backflow connector (which houses the check valve) is securely seated. Reconnect the electrical harness.

4. 4

   System Prime and Clear

   Reconnect the battery. Use a diagnostic tool to clear the 004376.03 fault code. Run a DEF system prime/dosing test to ensure the system builds pressure and the reverse flow valve operates correctly during the purge cycle.