3.2.76. SPN 157, FMI 2, Rail Pressure control: Pressure raw value is intermittentΒΆ

Description

The EEM4 monitoring system has detected pressure jumps in the rail pressure.

Possible causes are:

  • The rail pressure sensor connector is defective.
  • The rail pressure sensor is defective.
  • The fuel rail is defective.

Reaction in EEM

The FC is stored and the warning lamp is activated. Engine power and speed will be heavily reduced (Degradation Level 3). The CAN message indicates active fault. Engine functions dependent on the rail 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:

  • Check the rail pressure sensor wiring, the connectors and the contact surfaces of the connector pins (possible oxidation).
  • Check the engine fuel system visually to detect possible leaks.
  • Check the operation with another rail pressure sensor to see if the sensor is defective.

See Rail pressure sensor for reference.