Case IH F-1442-06 - ECU – Engine Control Unit (ECU): Fuel metering unit has an over-temperature error

The Engine Control Unit (ECU) has detected an over-temperature condition on its internal device driver (power stage) that controls the Fuel Metering Unit (MeUn). This is typically caused by the circuit drawing excessive current due to a short circuit (either to ground or to the battery) in the wiring harness, or an internal short within the fuel metering unit's solenoid coil.

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1. 1

   Check for related active codes such as DTC 5255 (Open load error), DTC 4155 (Intermittent electrical connection), or DTC 1565 (Fuel rail pressure deviation). If present, diagnose the electrical circuit first.

2. 2

   Inspect the wiring harness and connectors between the ECU and the Fuel Metering Unit for chafed wires, melted insulation, or loose contacts that could cause a short circuit.

3. 3

   Unplug the Fuel Metering Unit and measure the resistance across its coil terminals to check for an internal short circuit.

4. 4

   Check the low-pressure fuel lines from the high-pressure pump to the tank for damage or clogging, and verify proper gear pump pressure (the metering unit relies on fuel flow for cooling).

1. 1

   Power Down

   Turn off the machine, remove the key, and disconnect the battery to prevent further damage to the ECU.

2. 2

   Repair Wiring

   If the diagnostic checks revealed a short circuit or damaged wiring harness between the ECU and the metering unit, repair the wires or splice in a new connector pigtail.

3. 3

   Replace the Fuel Metering Unit

   If the wiring harness tests perfectly but the fault remains (or if the unit failed the resistance test), remove and replace the Fuel Metering Unit located on the high-pressure fuel pump.

4. 4

   ECU Replacement

   If the wiring is good and a new metering unit does not clear the code, the over-temperature event may have permanently burned out the internal driver inside the Engine ECU. In this case, the ECU must be replaced and reprogrammed.

5. 5

   Clear and Test

   Reconnect the battery, use a diagnostic tool (like the CNH EST) to clear the inactive fault codes, and run the engine to verify the repair.