Why does the Check Engine Light come on frequently in my Mercedes-Benz — could it be a faulty oxygen O2 sensor?

Home > Gari Forums > Mercedes Benz Forums > Mercedes Benz C Class Forums > Mercedes Benz C Class Sensor Issues Forums

Why does the Check Engine Light come on frequently in my Mercedes-Benz — could it be a faulty oxygen O2 sensor?

I own a Mercedes C200 W204, and the Check Engine Light CEL keeps coming on randomly. A local mechanic told me it might be due to a bad oxygen sensor. Considering the local fuel quality and frequent city driving in Karachi, how common are oxygen sensor failures in Mercedes cars here? What symptoms should I watch for, and how should I address this issue?

Talha Kyanii asked on 11 Oct 2025 11:13:11 am

1 Answer

7 views |

Gari Master - on 11 Oct 2025 11:14:11 am

Yes, a faulty oxygen sensor is a common reason for the Check Engine Light CEL in Mercedes-Benz cars, especially in Pakistan due to:

Poor fuel quality: Impurities and inconsistent octane levels can foul the sensor.

Frequent short city trips: The sensor may not reach optimal operating temperature, leading to buildup and degradation.

Contaminants: Dust and pollution in cities like Karachi can accelerate sensor wear.

Symptoms:

CEL with codes like P0130 to P0167 O2 sensor related.

Rough idling, reduced fuel efficiency.

Increased emissions o r failed emissions tests.

What to do:

Use a good OBD-II scanner to confirm the faulty sensor.

Replace the O2 sensor with an OEM o r high-quality aftermarket part.

Use quality fuel and avoid excessive idling.

Periodic engine tune-ups help prolong sensor life.