Mercedes are known for their luxurious interior comforts and exceptional engine performance. With the high technology used in the manufacturing process of building these machines, any small problem sends a signal to your vehicle’s onboard diagnostic system resulting in an illuminated warning light on the dashboard, including the check engine light. Below is a general guide with some common reasons as to why your Mercedes check engine light might be illuminated.
What is the check engine light?
The check engine light on the dashboard of your Mercedes is a warning signal that becomes illuminated when a problem arises. Mercedes is equipped with an onboard diagnostic system that uses many different sensors to detect a problem. When a sensor detects a problem, the electronic computer system then receives a signal resulting in an illuminated warning light. So, what causes the illumination of the check engine light?
Common causes of Mercedes check engine light illumination
There are a number of reasons that could cause a warning light on the dashboard to become illuminated including:
- Fuel cap: If the check engine light on your Mercedes dashboard is illuminated, you should first check the fuel cap. The fuel cap forms a seal around the fuel tank. So, when the cap is loose, broken, or missing altogether, vapors are able to escape and the fuel pressure is decreased. As a result, drivers will notice a reduction in fuel economy. Also, it will not pass a vehicle emissions test, as there is an increase in harmful emissions being released.
- Catalytic converter: The catalytic converter is integral in the Mercedes emission system as it aids in removing toxic carbon monoxide. However, the more you drive your vehicle the catalytic converter becomes clogged with dirt and debris resulting in failure. When failure occurs, drivers will notice a significant impact on the fuel economy and overall vehicle performance.
- Spark plugs: Spark plugs are responsible for creating a spark that ignites the air/fuel mixture within the cylinder allowing the engine to run. Over time, spark plugs and wires attached to them begin to wear out and fail. When this occurs, your Mercedes engine will not start as the spark is not able to ignite. It is common to have to replace the spark plugs of your vehicle over time.
- Oxygen sensor: The O2 sensor provides the proper air/fuel mixture to the engine control unit (ECU). When the oxygen sensor fails due to prolonged exhaust gas exposure, the ECU does not receive enough or receives too much fuel. When too much fuel reaches the engine the vehicle will exhibit dark smoke and an odor. However, with too little fuel reaching the engine, this results in engine failure.
- Mass airflow sensor: The Mass Airflow (MAF) sensor measures the amount of air entering the engine to help regulate the air/flow mixture. When this sensor is exposed to dirty air failure is inevitable. Failure of the MAF results in engine misfire, poor fuel economy, a decreased overall performance, as well as unnecessary and expensive engine damage.
How often is your check engine light on?
An illuminated check engine light may appear at all times, intermittently, or even appear to be flashing. Let’s take a look at what these mean:
- Intermittent illumination: If your check engine light is only illuminated in certain conditions, it is important to note any performance changes. Limit the amount of driving you are doing in this vehicle until you can have it assessed and a diagnosis
- Always on: When the onboard diagnostic system receives a signal that something is wrong, the check engine light will remain on. It is important to bring your vehicle to a trusted automotive expert whether there are performance issues or not.
- Blinking: A consistently blinking check engine light is a sign of a major problem. Immediately pull over into a safe location and have your vehicle towed to our auto repair shop for a thorough inspection.
Euro Plus Automotive
At Euro Plus Automotive, we have been helping drivers of Canoga Park, Woodland Hills, San Fernando Valley, and Los Angeles County, CA since 1984. Our factory-trained automotive experts specialize in German and Japanese vehicle service and repair work. If you find yourself experiencing vehicle difficulties, give us a call today to see how we can help with our same-day services.