Case IH 3910 (F-1442-02) - ECU – Engine ECU: Fuel metering unit intermittent electrical connection failure

The control module has detected an erratic, intermittent, or unstable electrical signal in the circuit that controls the fuel metering unit. An intermittent connection prevents the system from accurately controlling fuel rail pressure.

• VESTRUM CVX
• 240 Series Axial-Flow Combines
• Puma Series
• Farmall 40-45-50 (Cab/CVT models)
• A8000 Sugar Cane Harvesters
• A8800 Sugar Cane Harvesters
• A9900 Sugar Cane Harvesters

1. 1

   Check for Associated Active Faults: Use the Electronic Service Tool (EST) to check for other active codes. If codes 3735 (DTC 8355) or 3301 (DTC 1565) are present, diagnose and resolve them first.

2. 2

   Verify Power Supply: Check that the tractor's battery power supply has not been connected to an external power supply (like a jump box or external charger).

3. 3

   Inspect Low-Pressure Lines: Check the low-pressure fuel lines running from the high-pressure pump to the fuel tank for any restrictions or physical damage.

1. 1

   Locate the Component

   Locate the fuel metering unit, which is mounted directly on the Bosch high-pressure fuel injection pump (CP3 or similar).

2. 2

   Inspect the Connector

   Disconnect the electrical pigtail at the fuel metering unit. Inspect the pins for corrosion, moisture, backed-out terminals, or fretting (micro-wear caused by engine vibration).

3. 3

   Inspect the Harness

   Trace the wiring harness from the fuel metering unit back to the Engine ECU. Look for areas where the wire may be chafing against the engine block or brackets, causing an intermittent short to ground or an open circuit.

4. 4

   Perform Continuity Testing

   Using a multimeter, check the resistance of the wiring between the ECU pins and the metering unit connector while gently wiggling the harness to expose any intermittent breaks.

5. 5

   Test/Replace the Metering Unit

   If the wiring harness and connectors are in perfect condition, the internal solenoid coil of the fuel metering unit is likely failing intermittently due to heat and vibration. The unit must be replaced.

6. 6

   Clear Codes

   After repairing the wiring or replacing the valve, use the EST to clear the fault codes and run the engine to verify the repair.