Case IH 17608 (F-5380-06) - ECU – Engine ECU (Electronic Control Unit / EDC): Fuel metering unit is shorted between high side and low side

This fault indicates an electrical short circuit in the control circuit for the Fuel Metering Unit (also known as the Fuel Control Actuator, MPROP, or Suction Control Valve). The Engine Control Module (ECM) monitors the pulse-width modulated (PWM) signal sent to the metering unit. If the ECM detects that the high side (power supply) and low side (ground/control) circuits are shorted together, it logs this code. This condition prevents the ECM from regulating the fuel volume entering the high-pressure fuel pump, which can result in a derate, torque limitation, or engine stalling.

• VESTRUM CVX
• Case IH Austoft 9900
• Case IH Magnum
• Case IH Steiger
• Case construction equipment

1. 1

   Visual Inspection: Inspect the wiring harness routing from the Engine ECU to the fuel metering unit (located on the high-pressure fuel pump). Look for chafed wires, melted insulation, or corrosion at the connectors.

2. 2

   Component Resistance Test: Disconnect the fuel metering unit connector. Measure the resistance across the two pins on the metering unit itself. A healthy Bosch metering unit coil typically reads between 2.6 and 3.15 ohms. If the resistance is near 0 ohms, the solenoid is internally shorted.

3. 3

   Harness Short Test: With the ECU and the metering unit disconnected, check for continuity between the high-side and low-side pins on the engine wiring harness. If there is continuity, the wiring harness is shorted together and must be repaired.

4. 4

   Voltage Supply Check: Turn the key ON. Check the supply voltage at the metering unit connector (Pin 1 to vehicle ground). It should read between 4.75V and 5.75V depending on the specific system state.

1. 1

   Disconnect Power

   Turn off the machine and disconnect the negative battery cable to prevent ECU damage during repair.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a short in the harness, trace the harness back to the ECU. Repair or replace the damaged section of the wiring harness, ensuring it is properly secured away from high-heat or high-vibration areas.

3. 3

   Replace Fuel Metering Unit

   If the metering unit failed the resistance test (internal short): Clean the area around the high-pressure fuel pump to prevent debris from entering the fuel system. Disconnect the electrical connector from the fuel metering unit. Remove the mounting screws securing the metering unit to the high-pressure pump. Remove the old unit and discard the old O-rings. Lubricate the O-rings on the new metering unit with clean diesel fuel and carefully install it into the pump. Torque the mounting fasteners to OEM specifications and reconnect the electrical harness.

4. 4

   Clear Codes and Test

   Reconnect the battery, clear the fault codes using a diagnostic scan tool, and start the engine. Monitor the actual vs. commanded fuel rail pressure to ensure the new metering unit is regulating properly.