4326874 | Genuine Cummins® NOx Nitrogen Oxide Sensor

• Kenworth: T660, T680, T700, T800, T880, W900, C500
• Peterbilt: 320, 365, 367, 384, 386, 388, 389, 520, 567, 579, 587
• Freightliner: Cascadia, Columbia, Coronado, M2, 108SD and other Cummins-equipped chassis
• International: ProStar, LoneStar, HX, LT and other Cummins-equipped models
• Western Star: 4700, 4900, 6900
• Volvo: VNL
• Blue Bird: several Cummins-powered school buses

1. Emissions Control

Measures NOx levels in the exhaust to ensure they stay within legal limits (EPA, Euro 6, etc.)
Helps reduce harmful pollutants that contribute to:
Air pollution
Smog
Acid rain
Respiratory and cardiovascular problems

2. Enables SCR (Selective Catalytic Reduction) System

SCR uses Diesel Exhaust Fluid (DEF/AdBlue) to convert NOx into harmless nitrogen (N₂) and water (H₂O).
The NOx sensor provides feedback to control how much DEF to inject.
Ensures proper dosing to avoid:
Overuse (wasting DEF)
Underuse (failing emissions requirements)

3. Engine Performance Optimization

Works with the ECU (Engine Control Unit) to adjust:
Air-fuel ratio
Exhaust gas recirculation (EGR)
Combustion timing
Helps balance fuel economy, power, and emissions

4. Diagnostic and Safety Functions

Detects when emissions systems (like SCR or DPF) are failing or underperforming
Triggers check engine lights, fault codes, or limp mode if NOx levels exceed safe limits
Required for onboard diagnostics (OBD) compliance

• Check engine light (MIL)

• Poor fuel efficiency

• High DEF (AdBlue) consumption

• Failed emissions tests

• Error codes like P2201, P229F, P20EE, etc.