Case IH 3176 – Engine Electronic Control Unit (ECU) A-095: High pressure pump fuel delivery quantity in over run exceeds a maximum threshold

The Electronic Control Unit monitors the system for high-pressure fuel leakage during engine overrun (when the engine is decelerating or being driven by the vehicle's momentum). If the high-pressure fuel delivery quantity exceeds the maximum allowed threshold during this state, and the desired fuel rail pressure cannot be reached or maintained, the system assumes there is a leakage or a mismatch in the metering unit's set point.

• Steiger T4B
• Farmall
• 240 Series Axial-Flow Combines
• Puma Series Tractors
• Magnum Series Tractors
• Maxxum
• Steiger

1. 1

   Check the ECU (A-095) for the appropriate software version and re-flash if necessary, as software glitches can cause false overrun readings

2. 2

   Visually inspect the wiring harnesses and connectors between the ECU and the Fuel Metering Unit (Y-011) for bent or dislocated pins, corroded terminals, or broken wires

3. 3

   Perform a wiggle test by flexing the involved harnesses to reveal intermittent breaks or short circuits while monitoring the display for active faults

4. 4

   Use an Electronic Service Tool (EST) to check for other active electrical fault codes related to the fuel metering unit (such as shorts to ground/battery) and diagnose those electrical issues first

5. 5

   Check the mechanical operation of the fuel metering unit (Y-011), the pressure relief valve (PRV), and the rail pressure sensor

1. 1

   Inspect the Pressure Relief Valve (PRV)

   Check if the PRV is stuck open or leaking fuel back to the return line. If it is leaking during operation, replace the PRV.

2. 2

   Test the Fuel Injectors

   Perform a fuel return flow (back-leak) test on the injectors. If an injector has excessive internal leakage or is stuck open, replace the faulty injector.

3. 3

   Replace the Fuel Metering Unit (Y-011)

   If the PRV and injectors are functioning correctly, the Fuel Metering Unit on the high-pressure pump is faulty and unable to regulate the fuel volume correctly. Remove the old metering unit from the high-pressure pump and install the replacement.

4. 4

   Clear Codes and Test

   After replacing the faulty component, clear the fault codes using the EST and operate the machine in overrun conditions to verify the repair.