Case IH 3107 – Engine Controller: Engine Controller High Pressure Pump Metering Unit Circuit - Short Circuit To Battery

The electrical circuit controlling the high-pressure fuel pump's metering unit (Fuel Control Actuator, FCA, or M-Prop) has shorted to a 12V battery power source. This can be caused by a wiring harness short to an external power source, an internal short inside the metering unit itself, or an internal short inside the relay that supplies power to the unit.

• Farmall
• skid steer
• Steiger T4B
• Magnum Series 235 - 340 (Series 4)
• Steiger Series 350 - 600
• Skid Steer Loaders (SSL)
• Compact Track Loaders (CTL)
• 580 Super N Backhoes

1. 1

   Inspect the wiring harness between the Engine Controller, the High Pressure Pump Metering Unit, and the power supply relay for chafed, melted, or pinched wires contacting a 12V battery source.

2. 2

   Test Main Relay 1 (which provides power to the high-pressure pump fuel metering unit) for an internal short to the battery.

3. 3

   Disconnect the metering unit on the high-pressure fuel pump and test the component's pins for an internal short circuit.

4. 4

   Check the Engine Controller (ECU) pins to ensure they are not bent, corroded, or bridged by moisture or debris.

1. 1

   Disconnect Power

   Disconnect the machine's battery to prevent further electrical damage during the repair.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a short in the wiring harness to an external power source, repair or replace the damaged section of the harness.

3. 3

   Replace the Relay

   If Main Relay 1 is internally shorted, replace the relay with a new OEM unit.

4. 4

   Replace the Metering Unit

   If the wiring and relay are intact but the metering unit is shorted, remove the defective metering unit from the high-pressure fuel pump and install a new one. Torque the mounting bolts to OEM specifications (e.g., 8.0 N·m / 5.9 lb ft on NEF engines) and reconnect the electrical harness.

5. 5

   Clear Codes and Test

   Reconnect the battery. Use the Electronic Service Tool (EST) to clear the fault codes. Run the engine and verify that the rail pressure is within specification and that code 3107 does not return.