New Holland 3138 – ECU: Metering Unit Signal Not Plausible

The engine control unit has detected that the signal from the fuel metering unit is outside of its expected range or is otherwise illogical. This indicates a potential issue with the signal integrity, electrical connections, or the metering unit component itself, which can affect the common rail fuel system's performance.

• T-series
• Boomer
• T7000 series

1. 1

   Review related fault codes for fuel pressure or other sensors to provide additional context

2. 2

   Inspect electrical connections and the wiring harness leading to the fuel metering unit (typically located on the high-pressure fuel pump) for corrosion, damage, or loose connections

3. 3

   Inspect fuel filters for restrictions or contamination

4. 4

   Check for any leaks in the fuel system and ensure there is an adequate fuel supply to the high-pressure pump

5. 5

   Monitor the PWM (Pulse Width Modulation) output to the high-pressure pump using diagnostic software (a value above 24% at full load may indicate excessive fuel leakage from the overpressure valve or injectors)

1. 1

   Address electrical issues

   If any wiring or connector faults were found during the inspection, repair or replace the damaged components. Ensure all connections are clean and secure.

2. 2

   Replace fuel filters

   If the fuel filters are dirty or clogged, replace them with new, genuine filters to ensure proper fuel pressure.

3. 3

   Test the metering unit

   If wiring and filters are in good condition, use specialized diagnostic tools to observe the metering unit's signal and response to commands from the ECU.

4. 4

   Replace metering unit or high-pressure fuel pump

   If the metering unit is determined to be the cause of the fault, replace it. In many cases, the metering unit is an integral part of the high-pressure fuel pump (e.g., Bosch CP3) and must be replaced as a complete assembly.