New Holland ENG 3137 – Engine Control Unit (ECU / EDC / ECM): Fuel Metering Unit: Open Load of Metering Unit Output

The engine controller has detected an "open load" (open circuit) in the electrical circuit that controls the Fuel Metering Unit. This broken electrical connection prevents the ECU from controlling the fuel pressure.

• L220
• SR175
• T5.95
• T5.105
• T5.115
• T7 series
• T8 series
• T9 series
• CR9090
• CX8080
• CX8090

1. 1

   Use the Electronic Service Tool (EST) to verify if ENG 3137 is active. If other codes are present (like short-to-ground or sensor supply codes), diagnose those first.

2. 2

   Locate the Fuel Metering Unit on the back of the Bosch high-pressure fuel pump. Disconnect the plug and inspect the pins for corrosion, backed-out terminals, or loose contacts.

3. 3

   Using a multimeter, check the continuity of the two wires running from the Fuel Metering Unit connector back to the Engine ECU. Look for chafed wires, broken wires, or a disconnected harness.

4. 4

   Measure the resistance across the two pins on the Fuel Metering Unit itself. A healthy solenoid typically shows very low resistance (0.2 to 0.4 ohms). If the multimeter reads 'OL' (Open Loop) or infinite resistance, the solenoid has failed internally.

1. 1

   Depressurize fuel system

   Turn off the machine, remove the key, and wait for the fuel system pressure to drop. Clean the area around the high-pressure fuel pump thoroughly to prevent dirt from entering the fuel system.

2. 2

   Repair wiring harness

   If diagnostic checks revealed a broken wire or damaged connector pin between the ECU and the metering unit, repair the harness using OEM-approved splice connectors or replace the pigtail connector.

3. 3

   Replace Fuel Metering Unit

   If the solenoid tested open (infinite resistance), disconnect the electrical harness and remove the mounting screws securing the metering unit to the high-pressure fuel pump. Pull the unit straight out. Lubricate the O-rings on the new unit with clean diesel fuel, insert it into the pump housing, and torque the mounting screws to the manufacturer's specification.

4. 4

   Reassemble and test

   Reconnect the electrical harness. Prime the low-pressure fuel system if necessary. Start the engine, check for fuel leaks, and use the Electronic Service Tool (EST) to clear the inactive fault codes.