3.2.428. SPN 522391, FMI 31, SCR catalyst temperature sensors cross-connectedΒΆ

Description

The EEM monitoring system has detected that the temperature sensors are cross-connected.

Possible causes are:

  • The connectors are mixed between the temperature sensors.
  • The wiring is defective.
  • The temperature sensors are 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 wiring of the temperature sensors. Use the Service tool to monitor the fault codes and disconnect one sensor. For example, if the upstream temperature sensor is disconnected, the user should see the fault code related to the downstream sensor state.
  • Check the temperature sensor wiring, the connectors and the contact surfaces of the connector pins (possible oxidation).
  • Check the operation with another temperature sensor to see if the sensor is defective.

See Exhaust gas temperature sensor for reference.