Case IH 378 – Engine Control Module (ECM): Front Fueling current is too low / Fueling Actuator Number 1 - Open Circuit (Front)

The Engine Control Module (ECM) has detected an open circuit, high resistance, or abnormally low current in the circuit controlling the front fueling actuator, causing the engine to derate and run using only the rear three cylinders.

• MX Magnum
• STX Steiger
• Case IH Magnum Tractors (Models 215, 245, 275, 305, 335)
• Case IH Steiger series

1. 1

   Locate the front fueling actuator on the fuel delivery housing (Integrated Fuel System Module or IFSM), which is the actuator closest to the front of the engine.

2. 2

   Inspect the front fueling actuator and ECM harness connectors for pushed-back pins, corrosion, or moisture.

3. 3

   Measure the resistance across the pins of the front fueling actuator using a multimeter to check for an internal open circuit (infinite resistance) or out-of-spec resistance.

4. 4

   Pin out the wiring harness between the actuator connector and the ECM to check for continuity (broken wire) and continuity to ground (short to ground).

5. 5

   If wiring and actuator test good, check for a loss of boost voltage inside the ECM itself.

1. 1

   Prep the Machine

   Turn off the key switch and disconnect the batteries (negative cable first) to prevent arcing and protect the ECM.

2. 2

   Clean the Area

   Thoroughly clean the outside of the fuel delivery housing (IFSM) around the front fueling actuator to prevent dirt from entering the fuel system.

3. 3

   Remove the Actuator

   Disconnect the electrical connector from the front fueling actuator. Remove the mounting fasteners securing the actuator to the housing and pull the actuator straight out.

4. 4

   Install the New Actuator

   Lubricate the O-rings on the new actuator with clean engine oil. Carefully insert the actuator into the fuel delivery housing, ensuring the O-rings are not pinched.

5. 5

   Torque Fasteners

   Install the mounting fasteners and torque them to the specific OEM torque rating for your exact engine model.

6. 6

   Reassemble and Test

   Reconnect the electrical harness. Reconnect the battery cables (negative last). Clear the inactive fault codes using a diagnostic tool, start the engine, and verify that all 6 cylinders are now firing smoothly without the code returning.