New Holland ENG 3108 – Engine Controller (EDC / ECM): Fuel Metering Unit - Short Circuit to Ground

The Fuel Metering Unit regulates the amount of fuel entering the high-pressure fuel pump. This code triggers when the engine controller detects that the electrical control circuit for this unit has shorted to ground, which prevents the system from properly regulating fuel rail pressure.

• T4 Series (T4.75, T4.85, T4.115)
• T5 Series (T5.95, T5.105, T5.115)
• T8 Series
• L200 Series (L220)
• C200 Series
• SR175
• Magnum Series (235-340)
• Farmall Series

1. 1

   Visually inspect the wiring harness running from the Engine Controller (EDC) to the Fuel Metering Unit for chafing, melting, or pinched wires that could cause a short to the chassis or engine block.

2. 2

   Disconnect the plug at the fuel metering unit and the EDC to check for moisture, corrosion, or damaged pins.

3. 3

   Perform a harness continuity test using a multimeter to measure the resistance between the metering unit control wires and a known good chassis ground.

4. 4

   Test the pins on the fuel metering unit itself for an internal short to its own metal housing.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent electrical damage.

2. 2

   Isolate the Short

   Disconnect the engine wiring harness from both the Fuel Metering Unit and the Engine Controller (EDC).

3. 3

   Test the Harness

   Probe the signal and ground wires in the harness. If a short to ground is found in the wiring, repair the damaged section of the harness or replace the engine harness entirely.

4. 4

   Test the Metering Unit

   If the harness tests good, the internal solenoid of the fuel metering unit has likely failed and shorted to its casing. Remove the mounting bolts securing the metering unit to the high-pressure pump and replace the unit.

5. 5

   Reassembly & Clearing

   Reconnect all electrical connections and the battery. Use the CNH Electronic Service Tool (EST) to clear the inactive fault codes.

6. 6

   EDC Verification

   Start the engine and verify operation. OEM F5C diagnostic charts note that if the wiring and metering unit are perfectly intact but the fault persists, the Engine Controller (EDC) has suffered an internal error and must be reprogrammed or replaced.