DTC Description: Notes
WARNING: This page is about a different car, the 2018 Nissan Titan XD. However, it is still accessible from the selected car via links, so may be relevant.
The engine control module (ECM) monitors the NOx concentration in the engine's exhaust gases using an after treatment intake NOx sensor and an after treatment outlet NOx sensor. By comparing these two values, the ECM is able to determine the conversion efficiency of the SCR catalyst and dosing system.