Massey Ferguson 4332 – Engine ECU (EEM4): DEF System Pressure High (ECU) / SCR system ERROR: DEF over pressure detected.

The EEM4 monitoring system has detected that the Diesel Exhaust Fluid (DEF) pressure is above the normal operating range. This typically indicates a restriction or blockage in the return side of the DEF system, preventing the pump from relieving pressure.

• 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
• 7714 S
• 7715 S
• 7716 S
• 7718 S
• 7719 S
• 7720 S
• 7722 S
• 7724 S
• 7726 S

1. 1

   Check the DEF return line for kinks, crushing, or blockages caused by crystallized urea.

2. 2

   Inspect the DEF return line connector at the tank and the supply module to ensure it is not plugged with debris or crystallized DEF.

3. 3

   Check the DEF tank vent/breather filter, as improper venting can cause pressure irregularities.

4. 4

   Inspect the main filter inside the DEF supply module (pump) for severe restriction or collapse.

1. 1

   Relieve System Pressure

   Ensure the machine is turned off and the DEF system has completed its purge cycle (wait at least 5-10 minutes after key-off).

2. 2

   Inspect and Clear Lines

   Disconnect the DEF return line from the dosing module to the tank. Flush the line with warm distilled water to dissolve any crystallized urea. If the line is damaged or permanently kinked, replace it.

3. 3

   Clean Connectors

   Clean the return line connectors with warm distilled water and ensure the orifices are fully open.

4. 4

   Service the DEF Tank Vent

   Locate the DEF tank breather/vent filter. Remove and inspect it. If it is clogged with dust or crystallized DEF, replace it.

5. 5

   Replace the DEF Supply Module Filter

   Remove the filter housing cap on the DEF pump. Extract the old DEF filter cartridge and the equalizer element. Clean the housing with a lint-free cloth and warm distilled water. Install the new filter cartridge and O-rings, then torque the cap to OEM specifications.

6. 6

   Clear Codes and Test

   Reconnect all lines. Use a diagnostic service tool to clear the fault code (SPN 4332 FMI 0 / 004332.00) and restart the ECU. Run the engine and monitor the DEF pressure via the service tool to verify it remains within the normal operating range.