2.2.195. SPN 4334, FMI 31, SCR system: DEF pressure stabilisation failureΒΆ

Description

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

Possible causes are:

  • A possible air leakage in the inlet line.
  • The DEF supply module backflow connector is partially blocked.
  • The DEF supply module main filter is blocked.
  • The DEF supply module inlet filter is blocked.
  • The filter in the DEF tank sensor is blocked.
  • The used reducing agent (DEF/AdBlue) has been contaminated.

Reaction in EEM

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

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

Solution

First save the error log and then do the procedure that follows:

  • Examine the inlet line and inlet connectors to detect a possible air leakage in the system.
  • Change the DEF supply module backflow connector.
  • Change the DEF supply module inlet connector.
  • Change the DEF supply module main filter.
  • Check the used reducing agent for contamination and change it if necessary.