Cummins QSB 4.5L NOx Sensor 2018-2024: OEM 4384393

Advanced NOx Monitoring for Cummins QSB 4.5L Engines (2018–2024)

What is it?
The Cummins QSB 4.5L NOx Sensor (2018–2024), identified by OEM part number 4384393, is an emissions-related sensor designed for Cummins QSB 4.5-liter diesel engines produced between 2018 and 2024. This sensor measures the level of nitrogen oxides (NOx) in the exhaust stream and sends that information to the engine control unit (ECU), which uses it to manage exhaust aftertreatment processes and emissions-related systems.

Why choose this NOx Sensor?
This NOx sensor is engineered to Cummins’ original equipment specifications for the QSB 4.5L platform, ensuring accurate readings and reliable integration with the vehicle’s emissions management and SCR systems. When a NOx sensor becomes worn, contaminated, or fails, inaccurate exhaust data can lead to improper Diesel Exhaust Fluid (DEF) dosing, unexpected regeneration events, emissions warnings, or uneven aftertreatment behavior. Using the correct OEM-specified sensor supports stable emissions feedback and helps the system respond appropriately to real-time conditions.

Key Benefits
✅ Designed specifically for Cummins QSB 4.5L aftertreatment systems (2018–2024)
✅ Provides dependable NOx concentration data to the ECU
✅ Supports coordinated DEF metering and SCR control logic
✅ Direct replacement — no modifications required
✅ Built to withstand heavy-duty exhaust temperatures

Applications
This NOx sensor is suitable for medium- and heavy-duty vehicles and equipment powered by Cummins QSB 4.5L engines manufactured from 2018 through 2024. It’s commonly used in commercial trucks, vocational machines, industrial generators, agricultural equipment, and other platforms where precise emissions monitoring and regulated exhaust treatment are required.

Installation Notes
Before servicing, allow the exhaust and aftertreatment system to cool completely. Locate the existing NOx sensor in the exhaust or aftertreatment hardware, disconnect its electrical connector, and remove it from its mounting. Inspect the sensor port and wiring harness for contamination, corrosion, or damage before installing the new sensor. Thread in the replacement sensor and torque to factory specifications. Reconnect the electrical harness, clear any stored fault codes, and verify proper NOx readings using diagnostic tools.

Final Thoughts
If your Cummins QSB 4.5L-equipped vehicle is displaying NOx-related fault codes, uneven emissions behavior, or inconsistent aftertreatment performance, replacing the NOx sensor with the correct OEM-specified unit can help restore accurate emissions feedback and smoother aftertreatment operation. The Cummins QSB 4.5L NOx Sensor (OEM 4384393) plays a key role in maintaining emissions system stability and dependable performance across varied duty cycles.