3.2.180. SPN 3521, FMI 14, DEF quality sensor: Fluid quality unknownΒΆ

Description

The AdBlue suction module is installed in the SCR tank. The suction module is an independent unit which measures all the critical parameters of the aqueous urea solution.

Possible causes are:

  • The fault is an internal electronic fault in the suction module.
  • Poor quality reducing agent.
  • The AdBlue suction module is defective.

Reaction in EEM

The FC is stored and the warning lamp is activated.

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

  • Check the used reducing agent (DEF/AdBlue) quality. If there are any suspicions that a poor quality reducing agent has been used, the tank needs to be emptied and flushed.
  • Refill the DEF tank with valid reducing agent (AdBlue).

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 operation with another AdBlue suction module.