Selective Catalyst Reduction Components

On North American Specification (NAS) market vehicles only, there is a pre Selective Catalyst Reduction (SCR) Nitrogen Oxide (NOx) sensor module and a pre SCR NOx sensor located in the exhaust system before the SCR catalytic converter.

EU6 and NAS markets there is a post SCR NOx sensor module and a post SCR NOx sensor located in the exhaust system after the SCR catalytic converter.

The NOx sensor comprises an integrated heater and sensor control module. The sensor is used to measure the O2 and the NOx concentration in the exhaust gas of a diesel engine. The sensor and the control module are replaced as an assembly.

The NOx sensor control module sends a message via a private Controller Area Network (CAN) bus to the Powertrain Control Module (PCM) for monitoring the effectiveness of the SCR System.

Failure of a NOx sensor or the NOx emissions fail to reach a pre-determined threshold, the PCM will record a fault, messages will be displayed to the driver in the Instrument cluster (IC) and the Malfunction Indicator Lamp (MIL) will be illuminated.

Selective Catalyst Reduction Soot Sensor and Module - NAS market vehicles only 

The post Selective Catalyst Reduction (SCR) soot sensor is located in the exhaust system after the SCR catalytic converter.

The soot sensor comprises a sensor and sensor control module. The sensor measures the soot particles in the exhaust to evaluate the Diesel Particulate Filter (DPF) functionality. The sensor and the control module are replaced as an assembly.

The absorbed soot particles form conductive paths between the electrode combs in the sensor element. The control module measures the resistance between the electrode combs and sends a message via a private Controller Area Network (CAN) bus to the PCM to evaluate the DPF functionality.

For additional information, refer to: SELECTIVE CATALYST REDUCTION