The check engine light is a part of the onboard diagnostics system in your Mercedes. When illuminated, this indicates a problem within your onboard diagnostics system. Your Mercedes may develop an illuminated check engine light for several reasons. Determining the cause on your own may be difficult as many things can affect the onboard diagnostic system. Below we will dive into five common causes of an illuminated check engine light in your Mercedes-Benz.
Loose Gas Cap
The gas cap, also known as a fuel cap, on your Mercedes is a seal that is designed to hold the fuel in your tank and keep out dirt and debris. When your fuel cap is loose, broken, or even missing, it results in a reduction in fuel pressure, allowing fuel vapors to escape. When the fuel cap is not properly sealed, it may result in reduced fuel economy and an increase in emissions.
Failing Catalytic Converter
A catalytic converter is an exhaust emissions control device designed to reduce toxic gases and pollutants being released in the exhaust gas from an internal combustion engine. If the catalytic converter within your Mercedes becomes clogged with debris it can impact your vehicle’s fuel economy and overall performance.
Failed Spark Plugs
Spark plugs are made to send a spark through the cylinders, igniting the air-fuel mixture and allowing the engine to turn over and run. Over time, spark plugs may begin to fail with normal wear, resulting in engine misfire, decreased fuel economy, and decreased performance. If your spark plugs fail entirely, your vehicle may stop running altogether.
Faulty Oxygen Sensor
An oxygen sensor measures the amount of oxygen left in the exhaust gas, allowing the electronic control unit to ensure proper combustion within the engine. The oxygen sensor may fail due to prolonged exposure to extremely hot exhaust gases over time. The oxygen sensor fails, it allows too little or too much fuel into the engine. Not enough fuel in the engine may result in complete failure, while too much fuel in the engine will increase the amount of smoke your vehicle emits.
Faulty Mass Air Flow Sensor
The mass airflow sensor measures the amount of air entering the engine compartment to ensure the correct air-to-fuel ratio is supplied. The sensor begins to fail due to prolonged exposure to dirty air. When it begins to fail, or completely fails, you may begin to notice your engine is misfiring, your overall engine performance deteriorates, and there is a significant reduction in fuel economy.
As with any arising problem within your Mercedes, it is imperative to seek out diagnostic testing from a certified mechanic or technician. If your vehicle displays an illuminated check engine light and exhibits poor performance or smoke from the exhaust, pull over immediately and have your vehicle towed to an auto repair shop specializing in Mercedes-Benz service and repair.
Turning Wrenches: Your Mercedes Specialists
Turning Wrenches is Louisville, KY’s leader in quality and customer service since 2013. At our auto repair shop, we are proud to be able to offer:
- An ASA certified center
- ASE Certified mechanics and technicians
- After hours vehicle drop
- Towing services
At Turning Wrenches, we stand by all services and repairs we provide. Because we believe in quality over quantity, we take our time ensuring the job is 
completed to your satisfaction every time. Our services and repairs are backed by our 3-year/36,000-mile warranty.
Our friendly mechanics come with decades of experience with European service and repairs. We offer the highest-quality dealer services at a fraction of the price. From the time you drop your vehicle off until the keys are back in your hand, the entire experience is tailored to fit your desired budget and needs.
Turning Wrenches services Audi, BMW, Mercedes, and Mini. By limiting the brands we service, we are able to remain proficient on all of the latest diagnostic tools, updated technology, and service recommendations for those brands.
We provide complimentary Wifi while you wait for your vehicle. As we know, not everybody has time to sit and wait at a repair shop, so we can provide a rental vehicle or service such as Uber at a competitive rate.
Whether you need routine maintenance or emergency repairs, Turning Wrenches is here for you. Call us today to schedule your appointment.