4.2.269. SPN 521006, FMI 12, Nox conversion implausible

Description

EEM4 system detects error in NOx conversion.

Possible causes are:

  • The DEF supply module main filter is blocked
  • The used reducing agent (DEF/AdBlue) is invalid
  • The dosing valve is blocked
  • The DEF pressure line is blocked
  • The mounting boss is blocked
  • The DEF catalyst is deteriorated or blocked

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:

  • Change the DEF supply module main filter.(see Supply module)
  • Check the used reducing agent (DEF/AdBlue) quality. Change reducing agent if it doesn’t reply to ASP recommendation.
  • Check the DEF dosing valve by visually and with the Service Tool test function.
  • Check the DEF pressure line hose and the connector. Remove the hose to detect the possible blockage.
  • Remove the DEF dosing valve and check the mounting boss condition.
  • Check the DEF catalyst condition.