New Holland NH 3107 – Engine Control Unit (ECU): CC HS Power stage 1 fuel press. Control - SOURCE HIGH

The Engine Control Unit (ECU) detects a short circuit to battery voltage on the circuit controlling the Fuel Metering Unit (FCA/MPROP). When this circuit shorts to a high voltage source, the ECU cannot properly command the fuel pressure regulator, resulting in an engine derate, poor throttle response, or a forced shutdown to prevent over-pressurization.

• T5.95
• T5.105
• T5.115
• T7 series
• T8 series
• B110B Backhoe Loaders
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)

1. 1

   Ensure the machine is parked safely and the key is turned OFF.

2. 2

   Inspect the wiring harness running from the Engine ECU to the high-pressure fuel pump metering unit for chafed wires rubbing against the engine block or brackets.

3. 3

   Disconnect the plug at the Fuel Metering Unit and inspect for water intrusion, melted plastic, or pushed-out pins.

4. 4

   Using a multimeter, check the metering unit supply and signal wires for continuity to battery positive (B+) with the ECU disconnected. If voltage or continuity to B+ is present, the harness is shorted.

5. 5

   Measure the electrical resistance across the two pins of the Fuel Metering Unit. A healthy Bosch metering unit typically reads between 2.6 to 3.15 Ohms at 20°C (68°F). If it reads out of limits or shows a dead short, the actuator has failed internally.

1. 1

   Disconnect Power

   Disconnect the negative battery cable to prevent accidental spikes during repair.

2. 2

   Repair the Harness

   If the multimeter test revealed a short to battery in the wiring, trace the loom back to the ECU. Cut out the damaged section of wiring and solder/heat-shrink a new section of wire, or replace the engine harness section if heavily damaged.

3. 3

   Replace the Metering Unit

   If the wiring tests good but the metering unit failed the resistance test, clean the area around the high-pressure fuel pump thoroughly. Remove the Torx/Allen screws securing the metering unit to the CP3 pump, carefully pull the metering unit out, lubricate the O-rings on the new metering unit with clean diesel fuel, press it squarely into the pump housing, and torque the mounting screws to OEM spec (usually around 7-9 Nm).

4. 4

   Reassembly & Bleeding

   Reconnect the electrical connector. Reconnect the battery. Turn the key to the ON position to allow the electric lift pump to prime the low-pressure fuel circuit.

5. 5

   Clear Codes

   Connect an electronic service tool (EST) to clear the inactive NH 3107 fault code. Start the engine and verify that the check engine light remains off and rail pressure tracks desired parameters.