Cummins Truck NOx Sensor 2894939 / 5WK96674A / 2871978

This replacement emphasizes NOx sensing element using ceramic substrate and platinum electrode, maintaining signal drift within 3% in high-temperature exhaust; more stable than many low-cost aftermarket parts. Fits Cummins ISX, ISL, ISM engines; OEM numbers 2894939, 5WK96674A, 2871978 are direct replacements. Function: monitors NOx concentration in exhaust and sends data to ECU to adjust urea injection, ensuring SCR compliance. Installation difficulty: medium; remove existing sensor and clean carbon from thread hole; torque around 45 Nm; plug-and-play with no fault codes.