2.2.339. SPN 521023, FMI 31, EAT Monitoring: Possible exhaust line NOx sensor interchangeΒΆ

Description

The exhaust line NOx sensors may be cross-connected.

Possible causes are:

  • The upstream and downstream NOx sensors are interchanged.
  • The upstream or downstream NOx sensor is defective.

Reaction in EEM

The FC is stored and the warning lamp is activated. The CAN message indicates an active fault.

NOTE: The present fault is classified as an emission related fault. Engine power is reduced after a certain time which is defined by an authority.

Solution

First save the error log and check the following solutions:

  • Check that the upstream and the downstream NOx sensors are connected correctly.
  • Check that the NOx sensors are not cross-connected.
  • Check the NOx sensor wiring, the connectors and the contact surfaces of the connector pins (possible oxidation).
  • Check that the both NOx sensors are effective. Change the defective sensor to a new one.

See NOx sensor for reference.