Case IH F-5571-16 - ECU – Engine Control Module (ECM / ECU): Fuel pressure relief valve has reached maximum allowed open time

The Fuel Pressure Relief Valve (PRV) has exceeded its maximum allowed open time. This usually indicates that the valve's internal spring has weakened (causing it to leak/open prematurely) or that there is a severe fuel pressure regulation issue causing actual overpressure.

• MAGNUM AFS Connect
• 240 Series Axial-Flow Combines (7240, 8240, 9240)
• A8000 Sugar Cane Harvester
• A8800 Sugar Cane Harvester
• Magnum Series (215, 245, 275, 305, 335)
• Farmall Series (100C, 115U)
• MX Series
• SR220
• SR250
• SV250
• SV300
• TR320
• TV380
• 570NXT
• 580N

1. 1

   Verify the low-pressure fuel supply between the fuel filter and the inlet to the high-pressure pump (minimum 5 bar / 72 psi with engine loaded or unloaded).

2. 2

   Check the vacuum restriction between the inlet of the low-pressure pump and the fuel tank (must not exceed 5 inches of Hg / 127 mm Hg).

3. 3

   Inspect primary and secondary fuel filters for restrictions, and check fuel lines and Voss O-ring fittings for air ingress or leaks.

4. 4

   Perform a PRV leak-off test: Disconnect the return line from the PRV on the fuel rail, run the engine, and observe. If fuel leaks below the pop-off threshold, the valve is weak and must be replaced.

1. 1

   Depressurize

   Turn off the engine and allow the high-pressure fuel system to completely depressurize.

2. 2

   Clean

   Thoroughly clean the area around the common fuel rail and the PRV to prevent dirt from entering the high-pressure fuel system.

3. 3

   Remove

   Disconnect the fuel return line attached to the fuel pressure relief valve. Unscrew the faulty PRV from the common rail.

4. 4

   Install

   Thread the new PRV into the fuel rail and torque it to the manufacturer's exact specification (do not over-tighten, as this can distort the rail).

5. 5

   Reconnect & Prime

   Reconnect the fuel return line. Prime the fuel system using the hand primer pump to purge any air.

6. 6

   ECU Reset

   Connect a dealer diagnostic tool (such as CNH EST or Bosch ESI[truck]). You must clear the fault codes and perform a 'Reset of the working cycles of the fuel pressure relief valve (PRV)'. Note: If the system was locked into derate/inducement due to repeat detections, navigate to the 'Engine Restart Counter Reset' screen to unlock the system.