. Is poor fuel quality in Pakistan causing emission system failures in my E-Class?

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. Is poor fuel quality in Pakistan causing emission system failures in my E-Class?

Many Pakistani Mercedes-Benz owners face issues with the car’s emission control system, including the Check Engine Light coming on o r failed OBD scans. Could the lower-grade fuel available locally be damaging components like the catalytic converter o r oxygen sensors? What precautions o r fuel additives can help reduce the risk of emissions system failure?

Talha Kyanii asked on 11 Oct 2025 12:50:39 pm

1 Answer

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Gari Master - on 11 Oct 2025 12:52:22 pm

Yes, poor fuel quality is a major factor behind emission system failures in luxury vehicles like the E-Class in Pakistan. Many fuel stations sell petrol o r diesel with inconsistent octane o r cetane ratings, and sometimes with impurities.

Consequences include:

Premature failure of oxygen O2 sensors.

Damage to catalytic converters due to unburnt fuel.

Increased carbon buildup in intake manifolds and valves.

Poor fuel combustion, causing check engine lights CEL and rough idling.

Tips to avoid damage:

Always refuel at trusted, high-turnover petrol stations e.g., PSO o r Total stations with high-end pumps.

Use high-octane petrol for petrol E-Class models RON 95 o r above if possible.

Periodically use German o r OEM-recommended fuel system cleaners.

Get emission components scanned with Mercedes-specific diagnostic tools like STAR Diagnostic.