Standard Motor Products NOX041 Diesel Nitrogen Oxide NOx Sensor

The Standard Motor Products NOX041 is a direct-fit OE replacement nitrogen oxide (NOx) sensor engineered for diesel-powered vehicles. Designed to monitor and report nitrogen oxide emission levels, this sensor plays a critical role in the vehicle's Selective Catalytic Reduction (SCR) emissions control system, helping ensure compliance with federal and state emissions regulations.

NOx sensors are positioned in the exhaust stream to measure concentrations of nitrogen monoxide (NO), nitrogen dioxide (NO2), and nitrous oxide (N2O). This data is transmitted to the engine control module (ECM), which uses it to regulate the SCR system, DEF (diesel exhaust fluid) injection, and combustion parameters to minimize harmful emissions. A failed or degraded NOx sensor will typically trigger a check engine light and may result in failed emissions testing.

Key Features:

• Direct-fit OE replacement — engineered to match the original sensor's fit, form, and function
• High-temperature design built to withstand the harsh conditions of diesel exhaust systems
• Plug-and-play installation — no additional programming or calibration required
• Monitors NOx output to support proper SCR system and DEF injector operation
• Helps maintain emissions compliance and prevent diagnostic trouble codes (DTCs)
• Sold individually

Common causes of NOx sensor failure include soot buildup on the sensing element, ECU water intrusion, and wiring harness damage. After installation, always check OEM service information for any required reset or relearn procedures to ensure accurate system diagnostics.