Cummins QSB 6.7L, 4.5L NOx Sensor 2018-2024: OEM 5491422

Accurate NOx Feedback Starts Here: Cummins QSB Sensor (2018–2024)

What is it?
The Cummins QSB 6.7L & 4.5L NOx Sensor, identified by OEM part number 5491422, is a critical emissions-monitoring component used in Cummins QSB series diesel engines produced between 2018 and 2024. Installed in the exhaust or aftertreatment system, this sensor measures nitrogen oxide (NOx) levels in real time, providing essential feedback to the engine control unit (ECU) so downstream emissions hardware can function efficiently.

Why choose this NOx Sensor?
This NOx sensor is manufactured to Cummins’ original specifications for both the 6.7-liter and 4.5-liter QSB platforms, delivering accurate sensing and reliable integration with the engine’s emissions control strategy. When a NOx sensor degrades or fails, inaccurate readings can lead to improper Diesel Exhaust Fluid (DEF) dosing, emissions system warnings, and inconsistent aftertreatment performance. Replacing it with the correct OEM-specified sensor helps preserve dependable emissions monitoring and more coordinated exhaust treatment.

Key Benefits
✅ Engine-matched design for Cummins QSB 6.7L and 4.5L engines (2018–2024)
✅ Provides accurate NOx concentration feedback to the ECU
✅ Supports coordinated DEF dosing and SCR control logic
✅ Direct replacement — no modifications needed
✅ Built to withstand high-temperature exhaust environments

Applications
This NOx sensor is suitable for medium- and heavy-duty vehicles, industrial machines, and other equipment powered by Cummins QSB 6.7L or 4.5L diesel engines produced between 2018 and 2024. Typical applications include commercial trucks, agricultural units, construction equipment, generators, and other duty-cycle-intensive platforms where emissions monitoring and regulated exhaust treatment are essential.

Installation Notes
Before service, allow the exhaust and aftertreatment system to cool fully. With the engine off, disconnect the electrical connector from the existing NOx sensor and remove it from its mounting bung. Inspect the sensor harness and mounting threads for wear or contamination before installing the new unit. Thread in the replacement sensor and torque it to the manufacturer’s specifications, then reconnect the electrical harness. After installation, clear any stored fault codes and verify correct NOx readings with a diagnostic tool.

Final Thoughts
If your Cummins QSB-powered machine is showing NOx-related fault codes, erratic emissions behavior, or uneven aftertreatment performance, replacing a worn sensor with the correct OEM-specified unit can help restore accurate emissions monitoring and smoother SCR system operation. The Cummins QSB 6.7L & 4.5L NOx Sensor (OEM 5491422) plays a central role in maintaining coordinated emissions control and dependable performance across varied duty cycles.