Massey Ferguson 157.16 – Engine ECU (AGCO SISU POWER EEM3 or EEM4): Fuel Rail Pressure High (ECU) / Rail pressure ABOVE NORMAL

The engine control system has detected that the actual fuel pressure in the common rail is exceeding the requested/target pressure threshold set by the engine mapping. This can lead to engine power degradation (limp mode) or shutdown to protect the fuel system components from overpressure damage.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4707
• 4708
• 4709
• 4710
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 7714
• 7715
• 7716
• 7718
• 7719
• 7720
• 7722
• 7724
• 7726
• 6400
• 7400
• 8400
• 8600

1. 1

   Check the fuel return lines for blockages, kinks, or restrictions back to the tank, as a restricted return line will cause rail pressure to spike.

2. 2

   Inspect wiring and connectors at the Fuel Rail Pressure Sensor (3-pin) and the Fuel Pressure Control Valve / Metering Unit (M-Prop/DRV) for corrosion, backed-out pins, or wire chafing.

3. 3

   Verify sensor voltage by checking the 5V reference supply and the analog signal input at the ECU.

4. 4

   Monitor live data using a diagnostic service tool to compare the Desired Fuel Rail Pressure against the Actual Fuel Rail Pressure while cranking and at idle. If the sensor reads high pressure when the engine is off, the sensor is likely biased/failed.

1. 1

   Relieve Fuel System Pressure

   Ensure the engine is off and the high-pressure fuel system has had time to depressurize before opening any lines.

2. 2

   Test/Replace the Fuel Rail Pressure Sensor

   If diagnostic checks point to a biased sensor (reading high falsely), disconnect the 3-pin harness, unthread the sensor from the common rail (typically M14 x 1.5 or M18 x 1.5 thread), and install the replacement. Torque to OEM specifications.

3. 3

   Test/Replace the Fuel Pressure Regulator (Suction Control Valve)

   If the sensor is accurate and the pump is actually over-pressurizing the rail, the metering unit/pressure regulator on the high-pressure pump is likely stuck open. Remove the retaining bolts, extract the valve, lubricate the O-rings on the new valve with clean diesel fuel, and install it.

4. 4

   Bleed the System

   Prime the low-pressure fuel system to remove air.

5. 5

   Clear Codes

   Use a diagnostic scanner to clear the 00157.16 / SPN 157 FMI 16 fault code from the Engine ECU. Run the engine and verify that the code does not return.