Case IH 3137 (F-5380-05) - ECU – Engine Control Unit (ECU / ENG): Fuel metering unit has an open load error

The Engine Control Unit (ECU) has detected an open circuit (interrupted connection or lack of electrical load) in the circuit for the fuel metering unit. When the ECU detects an open load, it means the control signal is not reaching the solenoid, or the solenoid coil itself has failed open.

• VESTRUM CVX
• Case IH Magnum 235 - 340 (Series 4)
• Case IH 240 Series Combines
• Case IH Puma Series (165, 180, 195, 210, 225)
• Case IH Farmall Tractors (40, 45, 50, 115U)
• Case 580 Super N / 580N Tier 4 Backhoe Loaders

1. 1

   Check for external power interference by verifying that the tractor's battery power supply has not been connected to an external power supply. Disconnect if present and retest.

2. 2

   Use the Electronic Service Tool (EST) to check for other active fault codes, specifically those related to fuel pressure or Main Relay 1 (e.g., code 3114). Diagnose these first if present.

3. 3

   Inspect Main Relay 1, which provides the power supply to the high-pressure pump and fuel metering unit, as a defective relay can cause an open load error.

4. 4

   Inspect the wiring harness and connectors between the fuel metering unit and the ECU for loose contacts, breaks, shorts, corrosion, or damaged pins.

1. 1

   Relay Replacement

   If Main Relay 1 is found to be defective or intermittently dropping power to the metering unit, replace the relay and clear the codes.

2. 2

   Harness Repair

   If the diagnostic checks reveal a broken wire or damaged connector pin between the ECU and the fuel metering unit, repair or replace the affected harness section.

3. 3

   Component Replacement (Fuel Metering Unit)

   If the wiring, connectors, and relays are fully intact and supplying proper voltage, the internal solenoid of the fuel metering unit has likely failed open. Replace the fuel metering unit.

4. 4

   ECU Replacement (Last Resort)

   If the fault persists after verifying the wiring and replacing the metering unit and relay, the power stage inside the Engine Control Unit (ECU) may be defective. Replace the ECU and follow the appropriate Electronic Service Tool (EST) procedure to restore self-learning parameters.