Massey Ferguson 520317.31 – Engine Control Unit (ECU): Rail Pressure control: Pressure reduction interrupted

The engine's control system has detected that the actual fuel pressure inside the common rail is lower than the target pressure commanded by the system, or the pressure control valve is failing to regulate the pressure correctly.

• 4710
• 7724S
• 5712SL
• 7722S
• 7722
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 4708
• 7726S
• 4707
• 4709
• 5711SL
• 7718S
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 7720
• Tier 4 (2015-2021)
• 7715S
• 7724
• 4607M
• 4608
• 4609
• 4610
• 5611
• 5612
• 5613
• 5710
• 5711
• 6497
• 6612
• 6613
• 6713
• 7615
• 8450
• 8480
• 8727
• 8730

1. 1

   Check the primary and secondary fuel filters for severe clogging, water contamination, or gelling.

2. 2

   Inspect the low-pressure fuel lines for air leaks or restrictions. Verify the lift pump is supplying adequate pressure to the high-pressure pump.

3. 3

   Inspect the wiring harness and connector at the Fuel Rail Pressure Sensor and the Suction Control Valve (MPROP) for chafing, corrosion, or short circuits.

4. 4

   Perform a return flow (leak-off) test on the fuel injectors. Excessive return flow from one or more injectors will bleed off rail pressure.

5. 5

   Test the Suction Control Valve (SCV) on the high-pressure pump to see if it is sticking open/closed.

1. 1

   Replace Fuel Filters

   Drain the water separator, replace both the main fuel filter and the pre-filter, and bleed the fuel system of all air. Clear the code and test run the tractor.

2. 2

   Replace the Fuel Rail Pressure Sensor

   If the filters are clean and fuel supply is good, but the ECU is still reading erratic or low pressure, replace the fuel rail pressure sensor located on the common rail.

3. 3

   Replace the Suction Control Valve (SCV / MPROP)

   If the sensor is functioning properly, the pressure control valve on the high-pressure pump is likely failing to regulate fuel volume. Remove and replace the SCV.

4. 4

   Replace Injectors or High-Pressure Pump

   If the injector leak-off test reveals excessive return flow, replace the faulty injectors. If all else fails, the high-pressure fuel pump itself has failed internally and must be replaced.