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

Precision NOx Sensing for Cummins QSB Engines (2018–2024)

What is it?
The Cummins QSB 6.7L & 4.5L NOx Sensor, identified by OEM part number 5491422, is an emissions-diagnostic sensor designed for Cummins QSB series diesel engines produced from 2018 through 2024. This sensor monitors nitrogen oxides (NOx) in the exhaust stream, sending real-time data to the engine control unit (ECU) so the aftertreatment system can adjust Diesel Exhaust Fluid (DEF) dosing and optimize NOx conversion.

Why choose this NOx Sensor?
This NOx sensor is engineered to meet Cummins’ original specifications for the QSB 6.7-liter and 4.5-liter platforms, ensuring accurate readings and reliable communication with the engine’s emissions control systems. When a NOx sensor becomes worn or fails, the ECU may receive incorrect data, which can lead to improper DEF dosing, emissions system warnings, or reduced aftertreatment efficiency. Using the correct OEM-specified sensor helps maintain dependable emissions monitoring and supports coordinated aftertreatment behavior.

Key Benefits
✅ Designed for Cummins QSB 6.7L and 4.5L engines (2018–2024)
✅ Delivers accurate NOx concentration feedback to the ECU
✅ Helps support coordinated DEF dosing and SCR operation
✅ Direct replacement — no modifications required
✅ Built to withstand high temperature exhaust environments

Applications
This NOx sensor is suitable for medium- and heavy-duty vehicles equipped with Cummins QSB 6.7L or 4.5L diesel engines from 2018 through 2024. It is commonly used in commercial trucks, agricultural equipment, generators, and industrial machinery where emissions monitoring and regulated exhaust treatment are integral to daily operation.

Installation Notes
Before beginning service, ensure the exhaust system has cooled and the engine is off. Locate the NOx sensor in the exhaust or aftertreatment assembly, disconnect the electrical connector, and remove the old sensor. Inspect the mounting bung and wiring harness for corrosion or damage before installing the new sensor. Thread the replacement NOx sensor into place and hand-tighten before torqueing to factory specifications. Reconnect the electrical harness, clear any stored fault codes, and verify correct operation with appropriate diagnostics.

Final Thoughts
If your Cummins-powered equipment is exhibiting NOx-related warnings, erratic aftertreatment behavior, or emissions irregularities, replacing a worn or faulty NOx sensor with the correct OEM unit can help restore accurate exhaust monitoring and support smoother SCR system function. The Cummins QSB 6.7L & 4.5L NOx Sensor (OEM 5491422) plays a key role in maintaining coordinated emissions control and dependable vehicle performance.