5 Most Common Reasons Your Check Engine Light is On

January 14th, 2019 by

Gas cap check engine light on gauge cluster

It’s your worst nightmare. The check engine light has appeared. Don’t panic! Here are five of the most common reasons for a check engine light warning in your Mercedes-Benz.

1. Gas Cap

While your gas cap might not seem like the most important piece of equipment in your Mercedes-Benz, it actually carries a pretty important role. It maintains pressure in the engine and prevents fuel vapors from leaking out. In some cases, the gas cap check engine light will come on when the fuel cap has not been tightly secured.  We suggest that you unscrew the gas cap and re-tighten until it clicks, then allow the gas cap check engine light up to a day to reset. A loose, broken, or missing gas cap can cause your vehicle to start jerking and lower its efficiency. If the light remains on after a day, contact us at (909) 891-0121.

2. Oxygen Sensor

The oxygen sensor in your Mercedes-Benz monitors the percentage of unburned oxygen in the exhaust. Over time the sensor can get covered in ash, thereby reducing its effectiveness and leading to a decrease in gas mileage and an increase in emissions.

3. Catalytic Converter

Your catalytic converter reduces exhaust gases by converting carbon monoxide and other harmful materials into harmless ones. Most failures are down to faults with other items, but a damaged catalytic converter can mean your car will fail its emissions test.

4. Mass Airflow Sensor

The mass airflow sensor allows your car’s computer to know how much fuel is needed based on the amount of air coming into the engine. Faults can decrease efficiency, increase emissions, and cause your car to stall.

5. Spark Plugs and Wires

Spark plugs and wires are responsible for creating the original spark that initiates combustion within your Mercedes-Benz, but they can fail over time. If yours are faulty, misfires will occur.

Have Your Check Engine Light Diagnosed at Mercedes-Benz of Ontario

Your Mercedes-Benz check engine light is never something you should ignore. While the potential reasons for your check engine light displaying might not sound too serious, any one of these could develop into a much more complex issue over time. Rancho Cucamonga, Ontario, Fontana and Inland Empire drivers should stop by Mercedes-Benz of Ontario to have a Mercedes-Benz Master-Certified technician diagnose your vehicle and have your gas cap check engine light reset. Schedule an appointment today! Have questions about other Mercedes-Benz warning lights? We can help!

Posted in FAQ, Service, Service Tips