Cummins Series NOx Sensor 5WK96766C Replacement 4326861

This Cummins NOx sensor 5WK96766C directly replaces factory 4326861 and 5WK96766C numbers; universal compatibility, plug-and-play. It monitors NOx concentration in exhaust in real time and sends signals to the ECU to adjust injection and SCR system to ensure emissions compliance. Fits Cummins ISX, ISL, ISM series engines commonly used in heavy trucks and construction equipment. Replacing resolves torque limiter faults and warning lights, restoring power and easing emission tests. If the engine lacks power, fuel economy is poor, or the instrument cluster shows “post-treatment fault,” this sensor is aging and should be replaced.