Case IH 3140 – Engine Control Module (ECM): Metering Unit Signal Range Check - Signal Too Low

The electrical signal to or from the Fuel Metering Unit has dropped below the minimum acceptable threshold. This typically points to an open circuit, a short to ground in the wiring, or an internal failure of the metering unit's solenoid coil.

• skid steer
• Case IH SSL (Skid Steer Loaders)
• Case IH Magnum 235 - 340 (Series 4)
• Case IH Steiger
• Case IH Puma
• Case IH CTL (Compact Track Loaders)

1. 1

   Inspect the wiring harness and the electrical connector at the Fuel Metering Unit on the high-pressure fuel pump for chafed wires, corrosion, or loose pins.

2. 2

   Use a multimeter to check the continuity of the wiring between the Engine ECM and the metering unit to rule out an open circuit or short to ground.

3. 3

   Measure the resistance of the Fuel Metering Unit's solenoid coil to determine if it has failed internally (shorted or open).

4. 4

   Ensure there are no blockages in the low-pressure fuel tubes (e.g., clogged return lines from the pump to the tank) that could cause secondary fuel pressure anomalies.

1. 1

   Disconnect battery

   Disconnect the machine's battery to prevent electrical shorts.

2. 2

   Locate fuel injection pump

   Locate the high-pressure fuel injection pump on the engine. The Fuel Metering Unit is mounted directly to it.

3. 3

   Clean area

   Thoroughly clean the area around the metering unit to prevent dirt or debris from contaminating the high-pressure fuel system.

4. 4

   Disconnect harness

   Disconnect the electrical harness connector from the metering unit.

5. 5

   Remove fasteners

   Remove the mounting fasteners securing the unit to the pump.

6. 6

   Remove metering unit

   Carefully pull the old metering unit out of the pump housing.

7. 7

   Lubricate O-rings

   Lubricate the O-rings on the new metering unit with clean diesel fuel to prevent tearing during installation.

8. 8

   Install new unit

   Insert the new metering unit into the pump and tighten the fasteners to the specified torque.

9. 9

   Reconnect harness

   Reconnect the electrical harness.

10. 10

    Reconnect battery

    Reconnect the battery.

11. 11

    Prime and verify

    Prime the fuel system if necessary, and use the Case IH Electronic Service Tool (EST) to clear the fault codes and verify the repair.