Case IH F-1442-03 - ECU – Engine Control Unit (ECU): Fuel metering unit is shorted to battery voltage at the high side.

The fuel metering unit (also known as the fuel pressure control valve, MPROP, or FCA) controls the desired fuel flow to the high-pressure fuel rail. The control module monitors the power stage of this unit for electrical failures. If the module detects a short circuit to a high source (battery voltage) on the high side of the circuit, it logs this fault, which can result in an engine power loss or an inducement system lock.

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1. 1

   Use the Electronic Service Tool (EST) to check for related active faults (e.g., DTC 4465 / 3141, DTC 6655 / 3107, or DTC 7555 / 3912) and diagnose these concurrently

2. 2

   Verify the tractor battery power supply has not been connected to an external power supply (like a jump box or high-output charger) causing an overvoltage condition

3. 3

   Start the engine and check the battery voltage on the instrument cluster to ensure the alternator is not overcharging the system

4. 4

   Inspect the wiring harness between the Engine ECU and the Fuel Metering Unit (Component Y-011) for chafing, melted insulation, or exposed wires shorting to a 12V/24V power source

5. 5

   Disconnect the fuel metering unit and check the harness-side connector for voltage on the high-side pin with the key ON

6. 6

   Measure the resistance of the fuel metering unit solenoid coil to determine if the short is internal to the valve

1. 1

   Disconnect battery

   Turn off the machine, remove the key, and disconnect the battery negative terminal to prevent electrical arcing.

2. 2

   Locate fuel metering unit

   Locate the Fuel Metering Unit (Y-011), which is mounted directly to the Bosch high-pressure fuel injection pump.

3. 3

   Disconnect electrical connector

   Disconnect the electrical connector from the fuel metering unit.

4. 4

   Repair or replace harness

   If the harness is shorted: Locate the damaged section of the wiring harness between the ECU and the fuel metering unit. Splice and repair the wire using OEM-approved heat-shrink connectors, or replace the affected harness section.

5. 5

   Clean pump area

   If the fuel metering unit is internally shorted: Thoroughly clean the area around the high-pressure fuel pump to prevent dirt from entering the fuel system.

6. 6

   Remove mounting fasteners

   Remove the mounting fasteners securing the fuel metering unit to the high-pressure pump.

7. 7

   Extract fuel metering unit

   Carefully extract the old fuel metering unit.

8. 8

   Lubricate O-rings

   Lubricate the O-rings on the new fuel metering unit with clean diesel fuel.

9. 9

   Install new fuel metering unit

   Insert the new fuel metering unit into the pump and tighten the mounting fasteners to the OEM specified torque.

10. 10

    Reconnect electrical connector

    Reconnect the electrical connector.

11. 11

    Clear fault codes

    Reconnect the battery, turn the key ON, and use the EST to clear the fault codes.

12. 12

    Verify repair

    Start the engine and verify that the fault code does not return and that actual fuel rail pressure matches the requested fuel pressure.