3.2.256. SPN 5025, FMI 31, Upstream NOx sensor calibration values outside limitsΒΆ

Description

The EEM4 monitoring system has detected a calibration verification number mismatch.

Possible causes are:

  • The upstream NOx sensor is defective.
  • The upstream NOx sensor is installed incorrectly.
  • Possible tampering.

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 upstream NOx sensor assembly. Make sure the sensor is assembled according to the AGCO Power installation instructions.
  • Check the operation with another upstream NOx sensor to see if the sensor is defective.
  • A possible tuning chip may interfere with the NOx sensor signal.

See NOx sensor for reference.