3.2.380. SPN 521008, FMI 1, SCR system ERROR: DEF pressure build up failureΒΆ

Description

The EEM4 monitoring system has detected an SCR system ERROR. The SCR system cannot be pressurized.

Possible causes are:

  • The DEF supply module pressure connector is blocked.
  • The DEF supply module pressure hose is blocked.
  • The DEF dosing module is blocked.
  • The DEF supply module inlet connector is blocked.
  • The DEF supply module inlet connector pre-filter is blocked.
  • The DEF supply module inlet hose is blocked.
  • The DEF tank module is blocked.
  • A possible leakege in the system.

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:

  • Check the DEF supply module connectors to see the possible blockage.
  • Check the DEF SCR system pressure and inlet hoses to see the possible blockage.
  • Check the DEF supply dosing module to see possible blockage.