3.2.206. SPN 4332, FMI 16, SCR system ERROR: DEF dosing pressure above normalΒΆ

Description

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

Possible causes are:

  • The DEF backflow line is defective. (A possible blockage or a mechanical defect.)
  • The DEF supply module backflow connector is blocked.
  • The DEF supply module main filter is defective.
  • 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 bakflow line visually to detect any mechanical failure eg. if the hose is flattened.
  • Remove the backflow line from the supply module. Perform the dosing test with the service tool. There should be an ongoing flow from the hose. Check also the backflow connection from the DEF tank.
  • Change the DEF supply module backflow connector.
  • Change the DEF supply module main filter.
  • 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.