| CPC F01N 11/002 (2013.01) [F01N 3/208 (2013.01); G01M 15/102 (2013.01); F01N 2550/02 (2013.01); F01N 2900/1602 (2013.01)] | 20 Claims |

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1. A method for diagnosing a sensor of an exhaust aftertreatment system, the method comprising:
receiving, by a controller, a first indication of active exhaust gas flow from an engine to the exhaust aftertreatment system or a second indication of no or low exhaust gas flow to the exhaust aftertreatment system;
determining, by the controller and in response to the first indication, that an amount of an exhaust gas constituent in the exhaust gas flow at a particular location is expected to be at or below a first predefined value or that an exhaust gas constituent mass flow rate is expected to be at or below a second predefined value for a period of time;
determining, by the controller and in response to the second indication, that the amount of the exhaust gas constituent at the particular location is expected to be at or below the first predefined value for the period of time;
receiving, by the controller, data indicative of a sensed amount of the exhaust gas constituent from the sensor of the exhaust aftertreatment system during the period of time;
determining, by the controller and based on the sensed amount of the exhaust gas constituent, an amount of offset affecting the sensor of the exhaust aftertreatment system; and
initiating, by the controller, an action based on the determined amount of offset to diagnose the sensor, wherein the action comprises adjusting a reductant dosing based on the offset.
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