A NOx sensor plays a critical role in monitoring nitrogen oxide levels in the exhaust and helping the emissions system function properly. When the sensor begins to fail, inaccurate readings can disrupt engine management and aftertreatment performance. Recognizing the symptoms early helps prevent further emissions system issues.
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Check engine or emissions warning lights: One of the most common signs of a failing NOx sensor.
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Reduced engine power: The vehicle may enter derate or limp mode to maintain emissions compliance.
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Increased DEF consumption: Incorrect sensor data can cause excessive DEF dosing.
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Poor fuel efficiency: Engine adjustments based on faulty readings may increase fuel usage.
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SCR system fault codes: Errors related to NOx efficiency or DEF dosing may appear.
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Difficulty passing emissions tests: Inaccurate readings can lead to emissions compliance failures.
A failing NOx sensor can affect both drivability and emissions performance. Prompt diagnosis and replacement help restore proper system operation and prevent unnecessary strain on other emissions components.
