Massey Ferguson 157.03 – Engine Control Unit (ECU) / EEM: Fuel Rail Pressure Sensor High Voltage

The controller is reading a signal from the fuel rail pressure sensor that exceeds the normal operating range (typically greater than 4.6 Volts). This condition usually points to an electrical issue rather than an actual mechanical over-pressure situation.

• 5710SL
• 5711SL
• 5712SL
• 5713SL
• T4
• 4600 Series
• 4700 Series
• 4707
• 4708
• 4709
• 4710
• 5400 Series
• 5600 Series
• 5700 Series
• 5611
• 5612
• 5613
• 6400 Series
• 6600 Series
• 6700 Series
• 7400 Series
• 7600 Series
• 7700 Series
• 7614
• 7615
• 7616
• 7618
• 7619
• 7620
• 7622
• 7624
• 7626
• 8400 Series
• 8600 Series
• 8700 Series
• 2600H Series
• 2604H
• 2605H
• 2606H
• 600 Series

1. 1

   Inspect the wiring harness between the ECU and the fuel rail pressure sensor for an open circuit in the ground line or a short to a high-voltage source.

2. 2

   Verify that the reference voltage/power supply to the rail pressure sensor is correct and not shorting out.

3. 3

   Plug in a known good rail pressure sensor to see if the fault clears, which would indicate the original sensor has failed internally.

1. 1

   Safety First

   Turn off the machine, disconnect the battery, and allow the engine to cool. Crucial: Relieve the high-pressure fuel system before loosening any fittings to prevent severe injury from high-pressure diesel spray.

2. 2

   Access the Sensor

   Locate the fuel rail pressure sensor, which is threaded directly into the common fuel injector metering rail.

3. 3

   Harness Repair (If Applicable)

   If the diagnostic checks revealed a broken ground wire or a shorted power wire in the pigtail/harness, repair the wiring using OEM-approved connectors and clear the code.

4. 4

   Sensor Replacement (If Applicable)

   Disconnect the 3-pin electrical connector from the sensor. Unthread the defective sensor from the fuel rail. Install the new fuel rail pressure sensor and torque it to the manufacturer's exact specification (over-tightening can damage the rail; under-tightening will cause high-pressure leaks).

5. 5

   Reassembly and Testing

   Reconnect the electrical harness, reconnect the battery, and prime the fuel system. Use a diagnostic tool to clear the 00157.03 / SPN 157 FMI 3 fault code from the ECU. Start the engine and check for leaks and verify that the code does not return.