Abstract: The concepts described herein relate to a system, method, and/or apparatus for monitoring a NOx sensor that is arranged in an exhaust gas feedstream of an internal combustion engine downstream of an exhaust aftertreatment system to detect a fault related to the NOx sensor. This includes utilizing a catalyst efficiency model to detect occurrence of a fault that may indicate an in-range biased or stuck NOx sensor.

Abstract: In exemplary embodiments, methods and systems are provided for controlling emissions for a drive system for a vehicle. In one embodiment, the system includes: one or more first sensors configured to measure an engine temperature pertaining to an engine of the vehicle; one or more second sensors configured to measure an ambient temperature surrounding the vehicle; one or more third sensors configured to detect an amount of running time in which the engine has been running; and a processor coupled to the one or more first sensors, the one or more second sensors, and the one or more third sensors and configured to at least facilitate controlling emissions for the drive system based on the engine temperature, the ambient temperature, and the amount of running time in which the engine has been running.