GarageNation assesses upstream and downstream NOx sensor replacement for SCR system efficiency monitoring for compatible Mercedes GLA variants in Hyderabad. Typical estimate: ₹8,000 – ₹30,000; workshop time: 1–2 hours; coverage: 1 year on sensor.
Variant disclaimer: Mercedes GLA has multiple engines and transmissions. This page is not a claim that every variant uses this component; we confirm VIN, engine/transmission data and diagnostic results before approving work.
The model data does not identify a recurring nox sensor replacement fault for every Mercedes GLA. Diagnosis therefore starts with the reported symptoms, fault codes and measured values rather than an assumed model weakness.
Repair is considered where testing confirms a serviceable component and safe parts availability. Replacement is recommended only for confirmed wear, damage or a failed test. A written estimate follows diagnosis; no work starts without approval.
What does the NOx sensor do in a diesel car?
BS6 diesel cars use two NOx sensors — one before the SCR catalyst and one after. The 'before' sensor tells the ECU how much AdBlue to inject for optimal NOx reduction. The 'after' sensor confirms that the SCR catalyst is reducing NOx to acceptable levels. If the 'after' sensor shows NOx still high, the ECU triggers a fault and eventually prevents engine start to avoid continued illegal emission.
Can I drive with a NOx sensor fault code?
Initially yes, but the ECU counts driven kilometres with the fault active. After a threshold (model-specific, typically 800–1,000 km), the car enters limp mode. After a further distance, the car will not start. GarageNation stocks NOx sensors for BMW N47/B47, VW 2.0 TDI, and Mercedes OM651 diesel — most common replacements in Hyderabad.
Explore all NOx Sensor Replacement repairs or the Mercedes GLA service hub.
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