Case IH 3105 (F-5571-14) - ECU – Engine Control Unit (ECU): Fuel pressure relief valve is forced to open, perform pressure increase

This code indicates an issue within the high-pressure common rail fuel system. To determine mechanical wear-out or to protect the engine by sending the system into limp home mode, the Electronic Control Unit (ECU) forces the fuel pressure relief valve (PRV) open. If the valve is weak, it will bleed off rail pressure prematurely, causing low power and triggering this code.

• VESTRUM CVX
• 240 Series Axial-Flow (7230, 8230, 9230, 7240, 8240, 9240)
• Magnum MX210
• Magnum MX230
• Magnum MX255
• Magnum MX285
• Magnum 215
• Magnum 245
• Magnum 275
• Magnum 305
• Magnum 335
• Puma series
• Farmall 40
• Farmall 45
• Farmall 50
• Farmall 100C
• Farmall 115C
• SR220
• SR250
• SV250
• SV300
• TR320
• TV380
• 570NXT
• 580N
• 580SN

1. 1

   Low-Pressure Supply & Air Ingress: Install a clear test line between the low-pressure supply and the high-pressure pump inlet. Run the engine and observe for air bubbles. Very small random bubbles are acceptable, but a steady stream indicates an air leak.

2. 2

   Fuel Supply Pressure: Check the fuel pressure between the fuel filter and the inlet to the high-pressure pump. It should be a minimum of 5 bar (72 psi) with the engine loaded or unloaded. If it drops below 0.276 bar (4.0 psi) at any time, check the fuel pre-filter, primary filters, and tank for restrictions.

3. 3

   Vacuum Test: Vacuum between the inlet of the low-pressure pump and the tank should not exceed 127 mm (5 inches) of Hg.

4. 4

   Relief Valve Leak Test: Isolate the fuel pressure relief valve return line. When the rail pressure is high (e.g., 160 MPa), check to make sure the valve is not leaking fuel into the return system. If it is bleeding off pressure during normal operation, the valve is weak and must be replaced.

1. 1

   Depressurize

   Ensure the engine is off and the high-pressure fuel system has fully depressurized before opening any lines.

2. 2

   Clean

   Thoroughly clean the fuel rail and the area around the pressure relief valve to prevent debris from entering the common rail.

3. 3

   Remove

   Disconnect the fuel return line from the pressure relief valve. Unthread and remove the faulty pressure relief valve from the fuel rail.

4. 4

   Install

   Thread the new OEM Bosch/Case IH pressure relief valve into the fuel rail and torque to the manufacturer's exact specification.

5. 5

   Reconnect

   Reattach the fuel return line.

6. 6

   Bleed

   Prime the low-pressure fuel system to remove any introduced air.

7. 7

   Software Reset

   Connect a diagnostic tool (such as the Case IH EST or Bosch ESI[truck]). Clear the fault codes and, if required by the engine software, perform a 'Reset of the working cycles of the fuel pressure relief valve (PRV)'.

8. 8

   Test

   Run the engine and apply a load (e.g., hydraulic stall) to verify that rail pressure reaches its maximum target (often 24,000+ psi) without dropping or causing the new valve to open prematurely.