3.2.207. SPN 4332, FMI 18, SCR system ERROR: DEF dosing pressure below normalΒΆ

Description

The EEM4 monitoring system has detected an SCR system ERROR. The pressure during the metering control is too low in the DEF supply module.

Possible causes are:

  • A possible leakage in the DEF hoses, the connectors or the supply module. (A DEF leakage on the system pressure side or an air leakage on the suction side.)
  • The DEF supply module main filter is defective.
  • The DEF tank ventilation is blocked.
  • The used reducing agent (DEF/AdBlue) is 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:

  • Check the DEF system visually to make sure there is no leakage in the DEF connectors, the hoses or the supply module.
  • Change the supply module inlet connector.
  • Change the DEF supply module main filter.
  • Change the DEF tank suction filter.
  • Check that the tank ventilation is working properly.
  • Check the used reducing agent for contamination and change it if necessary.
  • Change the DEF supply module backflow connector.
  • Check the operation with another DEF supply module to see if the supply module is defective.