Massey Ferguson 157.16 – Engine ECU (EEM3 or EEM4): Fuel Rail Pressure High

Rail pressure ABOVE NORMAL. This condition is triggered when the measured fuel pressure in the common rail exceeds the commanded (desired) fuel pressure by a calibrated threshold.

• 4710
• 7724S
• 5712SL
• Interim Tier 4 (2012-2015)
• 7722
• 7722S
• 7615
• 5613
• 5713SL
• 7720S
• 7716
• 7718
• T4
• 7715
• 5710SL
• 7726
• 7616
• 7618
• 5608
• 4708
• 7619
• 7626
• 7726S
• 7624
• 4707
• 4709
• 5711SL
• 7614
• 7718S
• 5610
• 7620
• 7719
• 7714
• 7716S
• T4 (2015-2021)
• 5612
• 7622
• 7720
• Tier 4 (2015-2021)
• 5611
• 7715S
• 5609
• 7724
• 4700 Series
• 5600 Series
• 7600 Series
• 7700 Series
• 8600 Series
• 8700 Series

1. 1

   Check for Sensor Circuit Codes: Use a diagnostic service tool to check for other active codes (e.g., SPN 157 FMI 3 or 4), which indicate an electrical failure rather than an actual high-pressure condition.

2. 2

   Perform a Fuel System Integrity Check (FSIC): Monitor actual versus desired rail pressure for erratic readings or a 'saw-tooth' pattern.

3. 3

   Check the PRV Open Count: Check the Pressure Relief Valve (PRV) open count in the ECU's extended data records. If it exceeds the maximum allowed threshold (often 50 times), the valve's internal spring is compromised.

4. 4

   Inspect Wiring: Inspect the wiring harness and 120-pin connectors at the Engine ECU, fuel rail pressure sensor, and MPROP for damage, fuel/water intrusion, corrosion, or bent pins.

1. 1

   Verify the Fault

   Connect the diagnostic tool with the key ON, engine OFF, and verify the active 000157.16 fault code.

2. 2

   Harness Repair

   If the visual inspection in the diagnostic phase revealed damaged wiring between the ECU, the fuel rail pressure sensor, or the high-pressure pump control valve, repair the harness or connector pins as needed.

3. 3

   Replace the Sensor (If Applicable)

   If the diagnostic tool shows erratic rail pressure readings but the mechanical system tests fine, relieve the fuel system pressure and replace the Fuel Rail Pressure Sensor.

4. 4

   Replace the Pressure Relief Valve (If Applicable)

   If the PRV open count has exceeded the limit (e.g., >50 counts) or the valve is leaking/stuck, replace the Fuel Pressure Relief Valve on the common rail. Note: Extreme cleanliness is required when opening the common rail system to prevent microscopic contamination from destroying the injectors.

5. 5

   Reset ECU Counters

   If the PRV was replaced, you must use the diagnostic tool to reset the PRV open counter in the ECU.

6. 6

   Verify Repair

   Bleed the fuel system. Clear the fault codes, start the engine, and run an automatic fuel system test to verify that the actual rail pressure now matches the desired rail pressure and the code does not return.