Case IH 3910 (DTC 4155) - ECU – ECU / ECM: Fuel metering unit intermittent electrical connection failure

The fuel metering unit (MPROP, FCA, or Fuel Pressure Control Valve) regulates the amount of fuel entering the high-pressure fuel pump. This code triggers when the control module detects an unstable, dropping, or intermittent electrical signal to this valve.

• MAXXUM T4E
• 240 Series Axial-Flow Combines (7230, 8230, 9230)
• Puma series
• A8000 Sugar Cane Harvester
• A8800 Sugar Cane Harvester

1. 1

   Check for other active faults, specifically 3735 (DTC 8355) or 3301 (DTC 1565), and resolve them first

2. 2

   Verify that the machine battery has not been connected to an external power supply (like a booster or charger); disconnect if present and retest

3. 3

   Inspect the low-pressure fuel lines running from the high-pressure pump to the fuel tank for restrictions or damage

1. 1

   Locate the Fuel Metering Unit

   Locate the fuel metering unit, which is bolted directly to the Bosch high-pressure fuel pump on the engine.

2. 2

   Inspect the Wiring Harness

   Thoroughly inspect the wiring harness leading to the fuel metering unit. Look for chafed wires, melted insulation, or tight bends that could cause a break in the wire internally.

3. 3

   Inspect the Connector

   Disconnect the pigtail connector at the fuel metering unit. Check for backed-out pins, corrosion, moisture, or a broken locking tab that could cause the plug to vibrate loose during operation.

4. 4

   Test the Circuit

   Use a multimeter to check for continuity between the ECU and the metering unit connector. Wiggle the harness while testing to expose any intermittent breaks.

5. 5

   Repair or Replace

   If wiring damage is found, repair the harness or splice in a new connector pigtail. If the wiring and connector are in perfect condition, the internal solenoid of the fuel metering unit is likely failing intermittently and the unit itself must be replaced.