Massey Ferguson E 157 (3) – Engine Control Unit (ECU): Rail pressure sensor voltage above normal or open circuit

The control module is receiving a voltage signal from the fuel rail pressure sensor that exceeds the maximum expected threshold. This indicates an electrical issue, specifically an open circuit (such as a disconnected plug or broken wire) or a short to power, rather than an actual mechanical overpressure situation in the fuel rail.

• 5400 series
• 5600 series
• 6400 series
• 6600 series
• 7400 series
• 7600 series
• 7614-7626
• 7700 series
• 8400 series
• 8600 series
• 8700 series
• 5460
• 5465
• 5480
• 6465
• 6470
• 6480

1. 1

   Visually inspect the rail pressure sensor connector and the associated wiring harness for physical damage, corrosion, or a disconnected plug.

2. 2

   Use a multimeter to measure the resistance and voltage across the sensor pins. Check for an open circuit in the signal or ground wires, or a short to a voltage source.

3. 3

   Connect an Electronic Service Tool to read live data from the ECU. Check if the rail pressure reads at maximum voltage constantly, which confirms an open or short circuit.

1. 1

   Turn off the tractor

   Turn off the tractor, remove the key, and disconnect the battery to ensure safety and prevent further electrical shorts.

2. 2

   Locate the sensor

   Locate the fuel rail pressure sensor, which is threaded directly into the common fuel rail on the engine.

3. 3

   Disconnect the sensor

   Carefully depress the locking tab and disconnect the 3-pin electrical connector from the sensor.

4. 4

   Repair the wiring harness

   If the diagnostic checks revealed a broken wire or damaged connector, repair the wiring harness using an approved harness diagnostic/repair kit.

5. 5

   Clean the area

   If the wiring is intact and the sensor itself has an internal open circuit, clean the area around the sensor to prevent dirt from entering the fuel system.

6. 6

   Remove the faulty sensor

   Unscrew the faulty rail pressure sensor from the fuel rail.

7. 7

   Install the new sensor

   Install the new OEM rail pressure sensor and torque it to the manufacturer's exact specifications (do not over-tighten, as this can damage the rail).

8. 8

   Reconnect the connector

   Reconnect the 3-pin electrical connector.

9. 9

   Clear the fault code

   Reconnect the battery, turn on the ignition, and use the Electronic Service Tool to clear the E 157 (3) fault code.

10. 10

    Verify the repair

    Start the engine, check the fuel rail for any diesel leaks, and verify that the fault code does not return.