Massey Ferguson 1381.04 – Engine Control Unit (ECU): Fuel Pressure At The Inlet Of The High Pressure Pump Signal Voltage Issue

The controller has detected that the signal voltage from the fuel supply pump inlet pressure sensor (low-pressure fuel sensor) is below the normal operating range or shorted low.

• 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
• 5608
• 5609
• 5610
• 5611
• 5612
• 5613
• 7614–7626
• 7714–7726S

1. 1

   Inspect the wiring harness and electrical connector at the fuel supply pump inlet pressure sensor for rubbed wires, corrosion, or a direct short to ground on the signal wire

2. 2

   Disconnect the sensor and turn the key ON to verify it is receiving the correct reference voltage (usually 5V) and has a good ground from the ECU

3. 3

   Check the signal wire for continuity between the sensor connector and the ECU pin, ensuring it is not shorted to the ground wire or chassis

4. 4

   Ensure fuel filters are clean and that fuel is not gelled, as a best practice for fuel pressure codes

1. 1

   Power Down

   Turn off the tractor and disconnect the battery to prevent electrical spikes.

2. 2

   Locate the Sensor

   Locate the fuel supply pump inlet pressure sensor (often threaded into the fuel rail or near the inlet of the high-pressure fuel pump).

3. 3

   Harness Repair (If Applicable)

   If the diagnostic checks revealed a short to ground in the wiring harness, repair or replace the damaged section of the wiring.

4. 4

   Sensor Replacement

   If the wiring tests perfectly, the sensor has failed internally (shorted low). Disconnect the electrical connector. Unthread the faulty sensor (M18x1.5 thread size) and have a rag ready to catch residual fuel. Install the new OEM fuel pressure sensor and tighten to the manufacturer's torque specification.

5. 5

   Reassembly and Testing

   Reconnect the electrical connector and the battery. Use a diagnostic scan tool to clear the 001381.04 / SPN 1381 FMI 4 fault code. Run the engine to verify the code does not return and check the sensor fitting for fuel leaks.