NOx Sensor. Porsche 958 Cayenne 3.0L Diesel 2012-18

NOx Sensor.
The NOx Sensor is a emissions-control component designed to monitor nitrogen oxide (NOₓ) levels in the vehicle’s exhaust system. Installed within the exhaust stream, this sensor provides real-time data to the Engine Control Unit (ECU) to regulate combustion and after-treatment systems such as catalytic converters or SCR/AdBlue systems.

Fits:

• Porsche 958 Cayenne V6 3.0L Diesel 245HP 2012-18

Cars With Engine Codes:
CNRB

Diagram Ref No 17

What This Product Does:

• The NOx sensor continuously monitors levels of nitrogen oxides in your exhaust gases. This data is sent to the Engine Control Unit (ECU) or the vehicle’s emissions-control module.
• Based on NOx levels, the ECU (or emissions system) adjusts engine parameters (air-fuel ratio, exhaust after-treatment, DEF/AdBlue dosing in diesel/SCR systems, etc.) to ensure emissions stay within legal/environmental limits.
• Helps ensure compliance with environmental regulations and reduces harmful exhaust emissions — particularly NO and NO₂, which contribute to smog, acid rain, and health hazards.
• Supports proper functioning of components like catalytic converters or SCR (Selective Catalytic Reduction) systems by ensuring they receive accurate feedback for NOx removal. 

Symptoms Of Failure:

• Engine warning light / emissions fault appears on the dashboard — the ECU detects abnormal or missing NOx sensor signals.
  
• Reduced engine performance or “limp mode” — the ECU may limit engine output, or injection logic may suffer, leading to poor acceleration or unstable performance.
  
• Increased fuel consumption or poor fuel economy — incorrect NOx data can cause the engine management system to mis-manage the air/fuel mixture.
  
• Rough idle, misfires, or jerky acceleration — combustion may become uneven if exhaust feedback is wrong, especially under load or varying throttle.
  
• Failed emissions or inspection test, or excessive exhaust pollution — without a working NOx sensor, the emissions-control system can’t properly regulate NOx output.
  
• Potential damage to exhaust-aftertreatment components (e.g. catalytic converter or SCR system) — inaccurate NOx readings can lead to improper dosing or treatment, shortening component life.
  
  

Why Replacement Matters:

• Compliance with Emissions Regulations: For modern diesel (and many petrol) vehicles, a working NOx sensor is often required to meet compliance standards. Without it, you may fail emissions tests.
  
• Protects Engine Performance & Efficiency: A proper NOx sensor ensures the ECU has accurate exhaust feedback — leading to correct combustion, fuel economy, and stable power delivery.
  
• Prevents Further Damage: Faulty NOx readings can lead to improper exhaust after-treatment (e.g. over- or under-dosing AdBlue or mismanaging catalytic converter operation), which can damage costly components downstream.
  
• Environmental Responsibility: The sensor helps ensure harmful nitrogen oxides aren’t released in harmful quantities, reducing environmental harm and air-quality impact.

Related reference numbers
Related, superseded, cross reference or alternative numbers for comparison.

958907807D

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