Abstract: Systems and methods for diagnosing an exhaust aftertreatment system and mitigating the effects of a potential fault in the exhaust aftertreatment system are provided. A method includes: receiving, by a controller, data indicative of an amount of at least one of a gain or an offset affecting a sensor in an aftertreatment system; determining, by the controller, a compensation value based on the amount of the at least one of the gain or the offset; receiving, by the controller, data indicative of an amount of an exhaust gas constituent in the aftertreatment system; applying, by the controller, the determined compensation value to the data indicative of the amount of the exhaust gas constituent in the aftertreatment system to create compensated data; and initiating, by the controller, an action based on the compensated data.

Abstract: Systems and methods for diagnosing an exhaust aftertreatment system are provided. A method includes: receiving, by a controller and for each sensor of a plurality of sensors, one or more respective degradation level indicators indicative of one or more failure levels of the sensor, each of the one or more degradation level indicators determined using a corresponding performance parameter; receiving, by the controller and for each sensor of the plurality of sensors, one or more diagnosis threshold values; determining, by the controller, a multipoint diagnosis threshold value using the one or more diagnosis threshold values associated with the plurality of sensors; detecting, by the controller, an operational state of the aftertreatment system by comparing a performance value of the aftertreatment system to the multipoint diagnosis threshold value; and causing, by the controller, an indication of the operational state of the aftertreatment system to be displayed on a display device.

Abstract: Systems and methods for diagnosing an exhaust aftertreatment system are provided. A controller determines, for each sensor of a plurality of sensors, one or more performance parameters based on measurement data obtained from the sensor that is indicative of a performance of the sensor or a component of the exhaust aftertreatment system. The controller determines, for each performance parameter, a corresponding degradation level indicator indicative of a performance degradation of the corresponding sensor or the corresponding component of the exhaust aftertreatment system. The controller can determine, for each degradation level indicator, a corresponding diagnosis threshold value for detecting an operational state of the corresponding sensor or the corresponding component of the exhaust aftertreatment system.

Abstract: A method for diagnosing a NOx sensor is provided. The method includes receiving data indicative of operating conditions of an engine or an aftertreatment system; determining, during a first period of time, that an amount of NOx output from the aftertreatment system satisfies a low NOx operating mode condition; determining, during a second period of time, that operating conditions for ammonia slip are present based on data regarding operation of the aftertreatment system; responsive to the determination that operating conditions for ammonia slip are present, determining that the amount of NOx output from the aftertreatment system satisfies a high NOx operating mode condition; comparing a difference between a minimum value from the first period of time and a maximum value from a second period of time to a diagnostic threshold; and responsive to the difference being less than the diagnostic threshold, setting an alert.