4.2.49. SPN 1381, FMI 18, Fuel supply pump inlet pressure BELOW NORMALΒΆ

Description

The measured fuel supply pump pressure is too low.

Possible causes are:

  • Pre-filter dust loading capacity exceeded. Depending on fuel quality, this can be the most common cause if filter life is above 100 h
  • Pre-filter blocked (remarkable and sudden dust load from the tank).
  • Restriction/blockage in the fuel line from tank to the pump can be suspected if parts of the fuel line have been opened/serviced/changed recently
  • Vehicle filter is blocked

Sensor fault:

  • The fuel supply pump pressure sensor wiring is defective
  • The fuel supply pump pressure sensor power supply is not correct
  • The fuel supply pump pressure sensor is defective

Reaction in EEM

The FC is stored and the warning lamp is activated. Engine power will be reduced (Degradation Level 1). The CAN message indicates active fault. Engine functions that depend on the fuel supply pump pressure are not active.

Solution

First save the error log and then erase it. Restart the ECU after erasing the error log. If the fault occurs again during the next driving cycle, check the following paths:

  • Change the both/all fuel filter elements (and tank vent filter) according to the fuel filter service instructions.
  • If the filter service does not remove the issue, the restriction/too low pressure is caused by fuel line.

NOTE: If the error code occurs in cold climate/weather, make sure the tank is filled with winter grade diesel fuel!