3.2.378. SPN 521007, FMI 31, SCR system ERROR: DEF pressure stabilisation failureΒΆ

Description

The EEM4 monitoring system has detected an SCR system ERROR. The DEF supply module is unable to stabilize the system pressure.

Possible causes are:

  • The DEF supply module backflow connector is blocked.
  • The DEF supply module main filter is defective.
  • A possible leakege in the system.
  • The used reducing agent (DEF/AdBlue) has been contaminated.
  • The DEF supply module is defective.

Reaction in EEM

The FC is stored and the warning lamp is activated. The CAN message indicates active fault.

NOTE: The present fault is classified as an emission related fault. Engine power will be reduced after a certain time which is defined by an authority.

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 DEF supply module backflow connector.
  • Change the DEF supply module main filter.
  • Check the system visually to detect a possible leakage in the system.
  • Check the used reducing agent for contamination and change it if necessary.
  • Check the operation with another DEF supply module to see if the supply module is defective.