New Holland 3108 – ECM: Fuel Metering Unit Short to Ground

The Engine Control Unit (ECU) has detected a short circuit to ground in the electrical circuit of the Fuel Metering Unit (also known as the Fuel Control Actuator or Suction Control Valve). This means the control circuit for the solenoid has an unintended connection to the vehicle's chassis or another ground path. This condition affects the proper operation of the engine's fuel delivery system, causing the valve to behave erratically or become completely de-energized, which leads to a loss of fuel pressure control and can result in stalling, power loss, or failure to start.

• T6010
• T6020
• T6030
• T6040
• T6050
• T6060
• T6070
• T6080
• T6090
• T7.170
• T7.185
• T7.200
• T7.210
• T7.220
• T7.235
• T7.250
• T7.290
• T7.315
• T8.xxx

1. 1

   Visually inspect the wiring harness and connectors between the ECM and the fuel metering unit for chafed wires, broken wires, loose connections, or corrosion

2. 2

   Check for related active or stored fault codes (such as 3107 for short to battery or 3137 for open circuit) to help isolate the issue

3. 3

   Disconnect the fuel metering unit's electrical connector and measure resistance across its two terminals (expected: 2.6 to 3.15 ohms at 20°C/68°F). Readings outside this range indicate a faulty unit

4. 4

   With the fuel metering unit disconnected, check for continuity between each of the two pins on the harness side of the connector and chassis ground (continuity indicates a short in the wiring)

5. 5

   With the harness connector disconnected and ignition on, carefully measure voltage between the signal wire pin on the harness and chassis ground (a reading of 0V can confirm a short to ground)

1. 1

   Disconnect battery

   Disconnect the negative battery terminal to prevent electrical shock or damage to components before beginning repairs.

2. 2

   Access fuel metering unit

   Locate the fuel metering unit on the high-pressure fuel pump. Remove any necessary covers or components to gain access.

3. 3

   Perform Diagnostic Checks

   Follow the diagnostic steps outlined above to determine if the fault lies with the wiring or the fuel metering unit itself.

4. 4

   Repair wiring harness

   If diagnostic checks revealed a short to ground in the wiring harness, carefully repair the damaged section of wire, ensuring a secure and insulated connection.

5. 5

   Replace fuel metering unit

   If the diagnostic checks indicate a faulty fuel metering unit, unscrew the retaining bolts and remove the old unit (expect minor fuel spillage). Clean the mounting surface, lubricate the new O-rings with clean diesel fuel, install the new unit, tighten bolts to manufacturer specification, and reconnect the electrical connector.

6. 6

   Reconnect the Battery and Clear Fault Codes

   Once the repair is complete, reconnect the battery. Use a diagnostic tool to clear the 3108 fault code from the ECM.

7. 7

   Test the System

   Start the engine and let it run to ensure that the issue is resolved and the fault code does not reappear. Check for any fuel leaks.