Massey Ferguson E157.14 – Engine Control Unit (ECU): Fuel Rail Pressure Below Requested Pressure

The Engine Control Unit (ECU) has detected that the actual hydraulic fuel pressure inside the common rail is falling below the target threshold required for the current engine speed and load, which typically triggers an engine derate, loss of power, or engine stalling.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 4700 Series
• 4707
• 4708
• 4709
• 4710
• 5600 Series
• 6400 Series
• 6600 Series
• 6700 Series
• 7400 Series
• 7600 Series
• 7480
• 8400 Series
• 8600 Series
• 8700 Series
• 8650
• 8737

1. 1

   Lift Pump / Pre-Supply Flow Check: Open the bleed screw on the fuel filter housing (after the lift pump) and turn the ignition key to the ON position to check for a strong, steady flow of diesel. Weak flow indicates a failing lift pump or clogged tank pickup.

2. 2

   Filter Inspection: Check the primary (square pre-filter, if equipped) and secondary fuel filters for severe clogging, gelling, or water contamination.

3. 3

   Low-Pressure Line Inspection: Inspect the fuel lines from the tank to the high-pressure pump for kinks, blockages, or air leaks.

4. 4

   High-Pressure Leak Check: Inspect the common rail, injector lines, and pressure control valve for external leaks.

5. 5

   Sensor & Wiring Check: Inspect the wiring harness leading to the Fuel Rail Pressure Sensor for chafing, shorts to ground, or an open circuit.

1. 1

   Replace Fuel Filters

   Replace both the primary water separator/filter and the secondary fuel filter. Bleed the fuel system of all air.

2. 2

   Replace the Lift Pump

   If the lift pump failed the flow test in the diagnostic phase, replace it to restore adequate low-pressure supply to the high-pressure pump.

3. 3

   Test/Replace the Fuel Rail Pressure Sensor

   If low-pressure supply is excellent but the ECU still reads low pressure, the sensor itself may be failing or reading out of range. Replace the sensor (located directly on the fuel rail) and torque to OEM spec.

4. 4

   Perform an Injector Leak-Off Test

   If the sensor is good, one or more injectors may be stuck open and returning too much fuel to the tank, preventing the rail from building pressure. Identify and replace any leaking injectors.

5. 5

   Replace the High-Pressure Pump / Metering Unit

   If all filters, supply pumps, sensors, and injectors are functioning properly, the high-pressure fuel pump (or its attached metering unit) is internally worn and must be replaced.

6. 6

   Clear Codes

   Use a diagnostic scan tool to clear the active/logged DM1 and DM2 codes from the ECU and test drive the tractor under load.