Massey Ferguson E157.21 – Engine Control Unit (ECU): Fuel Rail Pressure Is Not As Expected During Startup Or Shutdown

Rail pressure sensor reading being out of range ("old") when starting or after stopping the engine, which often indicates that leaks have been detected in the common rail system.

• 7616
• 5612
• 7622
• Interim Tier 4 (2012-2015)
• 7614
• 5611
• 7615
• 5610
• 5613
• 7620
• 5609
• 7618
• 5608
• 7619
• 7626
• 7624
• 4707
• 4708
• 4709
• 4710
• 5710SL
• 5711SL
• 5712SL
• 5713SL
• 7714
• 7726S
• 8600 Series

1. 1

   Connect the Massey Ferguson EDT (Electronic Diagnostic Tool) to confirm the active error code and monitor live fuel rail pressure data during engine cranking and shutdown.

2. 2

   Visually inspect the entire common rail, high-pressure fuel lines, and injector connections for any signs of physical fuel leaks.

3. 3

   Check the fuel filter element. A blocked or heavily restricted fuel filter can cause unexpected pressure drops.

4. 4

   Test the fuel rail pressure sensor wiring harness for continuity, shorts, or corrosion that could cause erratic readings to the ECU.

1. 1

   Depressurize fuel system

   Ensure the engine is off and allow sufficient time for the high-pressure fuel system to depressurize before opening any lines.

2. 2

   Address physical leaks

   If physical leaks are found in the common rail or high-pressure lines during the diagnostic phase, tighten the fittings to the manufacturer's specified torque. If a line is damaged or the leak persists, replace the affected high-pressure line.

3. 3

   Replace fuel filter

   If no leaks are found but the fuel filter is old or suspected to be blocked, remove and replace the fuel filter element. Prime the fuel system to remove any trapped air.

4. 4

   Replace fuel rail pressure sensor

   If the filter is clean and there are no leaks, the rail pressure sensor itself is likely faulty (giving "old" or inaccurate readings). Remove the defective fuel rail pressure sensor from the common rail and install a new one.

5. 5

   Clear error code

   Reconnect the battery (if disconnected) and use the EDT diagnostic tool or the dashboard control unit to clear the error code.

6. 6

   Verify repair

   Start the engine and verify that the fuel rail pressure reaches the expected target without logging the E157.21 code again.