Possible Causes
Faulty Nitrogen Oxide (NOx) Sensor
Nitrogen Oxide (NOx) Sensor harness is open or shorted
Nitrogen Oxide (NOx) Sensor circuit poor electrical connection
الأسباب المحتملة
Possible Symptoms
Engine Light ON (or Service Engine Soon Warning Light)
الأعراض المحتملة
Description
The aftertreatment system is equipped with two NOx Sensors and modules. The upstream Nitrogen Oxide (NOx) Sensor 1/1 is located before the SCR Catalyst and is permanently connected to a corresponding NOx Sensor Module mounted on the right frame rail. The downstream NOx Sensor 1/2 is located at the outlet of the SCR Catalyst and is permanently connected to a corresponding NOx Sensor Module also mounted on the right frame rail. The NOx Sensors and NOx Sensor Modules are calibrated to each other and must be replaced as an assembly. The two NOx Sensor and Module assemblies are not interchangeable. The NOx Sensor Modules are smart devices and communicate with the Powertrain Control Module (PCM) over the J1939 Data Link. The NOx Sensor Modules perform their own internal diagnostics and report malfunctions back to the PCM. The NOx Sensors are used to monitor the efficiency of the SCR Catalyst. The PCM will illuminate the MIL lamp immediately after the monitor runs and fails. The PCM will turn off the MIL Lamp after the monitor runs and passes for three consecutive trips.
