Cummins NOx Sensors
Cummins NOx sensors measure nitrogen oxide levels in diesel exhaust systems and are critical for proper SCR (Selective Catalytic Reduction) aftertreatment operation. These sensors send real-time emissions data to the engine control module to regulate DEF dosing and maintain emissions compliance. At Advanced Truck Parts, we supply Cummins NOx sensors designed for reliable performance in heavy-duty diesel engines.
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Cummins NOx Sensors in SCR Aftertreatment Systems
Modern Cummins engines rely on multiple NOx sensors to monitor exhaust gases before and after the SCR catalyst. This data allows the ECM to control Diesel Exhaust Fluid (DEF) injection and ensure the system reduces nitrogen oxide emissions effectively.
Typically, Cummins aftertreatment systems use:
- Upstream NOx sensors located before the SCR catalyst
- Downstream NOx sensors located after the SCR catalyst
These sensors work together with DEF pumps, dosing valves, and SCR catalysts to maintain emissions compliance and proper engine performance.
Common Cummins Engine Applications
Cummins NOx sensors are widely used across several heavy-duty and medium-duty diesel platforms.
- Cummins ISX CM870, CM871, CM2250, CM2350
- Cummins X15 Efficiency and Performance Series
- Cummins ISB 6.7L engines
- Cummins ISC and ISL engines
- Kenworth, Peterbilt, Freightliner, and International trucks
Because sensor calibration and connector types vary by emissions generation, matching the correct part number is important when replacing a NOx sensor.
Common Cummins NOx Sensor Failure Symptoms
- Check engine or SCR warning lights
- NOx sensor fault codes
- Incorrect DEF dosing or SCR efficiency faults
- Engine derate or limited power mode
- Failed emissions system diagnostics
NOx sensors can fail due to prolonged heat exposure, contamination from exhaust deposits, wiring damage, or internal electronic failure. Replacing a faulty sensor helps restore proper SCR monitoring and prevent further aftertreatment issues.
Upstream vs Downstream NOx Sensors
Most Cummins SCR systems use two sensors with different functions:
- Upstream sensor: measures engine-out NOx levels to determine how much DEF should be injected.
- Downstream sensor: verifies SCR catalyst efficiency by measuring NOx levels after treatment.
If either sensor fails, the ECM may trigger fault codes and reduce engine power until the system is repaired.
Verify Fitment Before You Buy
NOx sensors vary depending on engine model, emissions configuration, and connector type. To confirm compatibility before ordering, provide:
- Engine Serial Number (ESN)
- Truck year / make / model
- Current NOx sensor part number
- Photos of the sensor or wiring connector if available
This information helps ensure the correct Cummins NOx sensor is selected for your application.
Why Buy Cummins NOx Sensors from Advanced Truck Parts?
- Fitment verification before purchase
- Reliable emissions and aftertreatment components
- Fast shipping to reduce truck downtime
- Support for fleets, repair shops, and owner-operators
- Competitive pricing on diesel emissions parts
