Case IH 2765 (519751.02) - DEC – Engine Control Unit (ECU) / DEC (Diesel Engine Controller): Fuel rail pressure has exceeded the minimum limit

The Electronic Control Unit (ECU) monitors the fuel pressure control via the fuel rail pressure sensor. If the ECU determines that the rail pressure is lower than expected based on engine speed-dependent thresholds—and is less than the necessary pressure needed to perform proper fuel injection—this fault is triggered.

• VESTRUM CVX
• Case IH 240 Series Axial-Flow Combines
• Case IH Steiger Series
• Case IH Magnum, Puma, and Maxxum Series tractors

1. 1

   Inspect the high-pressure fuel system for internal or external leakages.

2. 2

   Check the Pressure Control Valve (PCV) for tightness in the closed position by commanding it to 100% PWM.

3. 3

   Check the PCV for proper opening by commanding it to 0% PWM (which should result in no pressure).

4. 4

   Check the high-pressure fuel pump for overall efficiency and output.

5. 5

   Check the fuel injectors for tightness (excessive return flow/leak-off).

6. 6

   Check the wiring harness for the fuel rail pressure sensor and PCV for external electrical faults (shorts, opens, or erratic data causing the .02 FMI).

1. 1

   Verify the Fault

   Connect the Case IH Electronic Service Tool (EST) to verify that fault code 2765 / 519751 is active.

2. 2

   Visual Inspection

   Inspect all high-pressure fuel lines, the fuel rail, and connections for visible external leaks. Ensure the low-pressure fuel supply is adequate and fuel filters are not restricted.

3. 3

   Electrical Testing

   Inspect the wiring harness and connectors for the fuel rail pressure sensor (B-015) and the Pressure Control Valve (PCV) for damage, corrosion, or loose pins. Test the sensor's voltage to ensure it is not reporting erratic data.

4. 4

   PCV / Metering Unit Test

   Using the diagnostic tool, perform a sweep test on the PCV. Command the valve to 100% PWM to verify it closes tightly, and 0% PWM to verify it opens. Replace the PCV if it fails to respond correctly.

5. 5

   Injector Leak-Off Test

   Perform a manual injector return flow (leak-off) test. If one or more injectors are bleeding off excessive rail pressure internally, replace the faulty injector(s).

6. 6

   High-Pressure Pump Test

   If the PCV, sensor, and injectors are functioning properly and there are no leaks, test the high-pressure fuel pump's output. If the pump cannot generate or maintain the required minimum pressure, it must be replaced.

7. 7

   Clear and Verify

   After replacing the faulty component, bleed the fuel system, clear the fault codes using the EST, and test run the engine under load to verify the rail pressure remains within specified limits.