3.2.139. SPN 3228, FMI 14, Downstream NOx sensor supply voltage out of rangeΒΆ

Description

The measured NOx sensor supply voltage is out of the operating range.

Possible causes are:

  • The NOx sensor wiring is defective.
  • The alternator is defective.
  • The voltage converter is defective (optional).
  • The NOx sensor is 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 NOx sensor wiring, the connectors and the contact surfaces of the connector pins (possible oxidation).
  • Check the alternator operation. Measure the alternator voltage and the battery voltage.
  • Check the voltage converter operation, if there is one in the system.
  • Check the operation with another NOx sensor to see if the sensor is defective.

See NOx sensor for reference.