4.2.271. SPN 521007, FMI 14, SCR system ERROR: DEF pressure line or dosing valve blockedΒΆ

Description

The EEM4 monitoring system has detected an SCR system ERROR. The DEF supply module pressure line or the DEF dosing valve is defective.

Possible causes are:

  • The DEF supply module pressure line is defective. (A possible blockage or a mechanical defect.)
  • The DEF supply module main filter is defective
  • The DEF dosing valve 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 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 pressure line visually to detect any mechanical failure eg. if the hose is flattened.
  • Remove the pressure line from the supply module and perform the dosing test with the service tool to see if the hose is blocked. The fluid should flow out from the pressure line hose.
  • Change the DEF supply module main filter.
  • Check the system visually to detect a possible leakage in the system.
  • Check the used reducing agent (DEF/AdBlue) for contamination and change it, if necessary.
  • Remove the DEF dosing valve and check the nozzle of the dosing valve to see the possible blockage.
  • Check the operation with another DEF supply module to see if the supply module is defective.