If you’re a Mercedes-Benz owner and you notice that the Check Engine Light (CEL) in your vehicle stays illuminated constantly, it’s important not to ignore it. The check engine light is an essential warning indicator that alerts you to potential issues with your car’s systems. If this light stays on while you drive, it means something is not right, and you need to take care of it immediately.
Faulty Oxygen Sensor
The oxygen sensor measures the oxygen content in the exhaust gases. A malfunctioning sensor can cause incorrect readings, leading to the CEL illumination. It is important to address this issue promptly, as a faulty oxygen sensor can negatively affect fuel efficiency and emissions.
Loose or Faulty Gas Cap
A loose, damaged, or missing gas cap can trigger the CEL. The gas cap helps maintain the proper pressure in the fuel system, and when it is not properly sealed, it can cause the CEL to come on. Ensure that the gas cap is securely tightened, or consider replacing it if damaged.
Malfunctioning Mass Airflow (MAF) Sensor
A malfunctioning MAF sensor can trigger the CEL. The MAF sensor measures the amount of air entering the engine. If it fails or becomes dirty, it can provide inaccurate readings, resulting in improper fuel-air mixture and performance issues.
Faulty Ignition Coil
Ignition coils and spark plugs play a crucial role in the combustion process. If one or more of these components are faulty, it can cause misfires, poor engine performance and trigger the CEL.
Emission Control System Problems
The emission control system in your Mercedes-Benz includes various components such as the catalytic converter, exhaust gas recirculation (EGR) valve, or evaporative emissions (EVAP) system. If any of these components fail or malfunction, it can result in increased emissions and trigger the CEL.
Sensor Malfunctions
Mercedes-Benz vehicles are equipped with numerous sensors that monitor various systems, such as the engine, transmission, or emissions. If any of these sensors fail or provide inaccurate readings, it can cause the Check Engine Light to illuminate.
What You Should Do If Your Mercedes CEL Illuminates
Seeing the CEL on can be worrisome, but it’s important to stay calm and avoid panicking as you drive. It’s equally crucial that you address the issue as soon as possible. The CEL can indicate a range of problems, from minor issues to more significant malfunctions. Ignoring the problem now may result in further damage and potentially expensive repairs.
- Check for Obvious Issues: When the light comes up, perform a visual inspection on your vehicle. Look for any noticeable problems. Sometimes, a minor problem, like a loose gas cap, can trigger the light. If you find any visible issues, address them accordingly. Tighten the gas cap securely and fix any loose or damaged components you come across.
- Check for Codes with an OBD-II Scanner: To gain a better understanding of the underlying issue causing the CEL to illuminate constantly, you’ll need to retrieve the trouble codes stored in your vehicle’s onboard diagnostic system. Take your car to a trusted repair shop that has an OBD-II scanner, where they can offer code reading services.
- Determine the Severity: From the diagnostic trouble codes, you can find out the severity of the issue. Some codes may represent minor problems, such as faulty sensors, while others can indicate more significant issues that require immediate attention.
- Consult a Professional: It’s advisable to take your Mercedes to an authorized service center or a qualified mechanic with experience in Mercedes-Benz vehicles. They have the necessary expertise and specialized tools to diagnose and resolve the problem accurately. Explain the symptoms you’ve observed and proceed with the troubleshooting process.
Book An Appointment at Momentum Motorworks for CEL Issues
In need of expert assistance for your Mercedes 
constant CEL illumination? We can help! At Momentum Motorworks, we are proud to be the go-to auto repair shop for Mercedes owners from Alabaster, Homewood, Helena, Hoover, Mountain Brook, Vestavia, and Birmingham, AL.
Our highly-trained technicians have in-depth knowledge and access to the latest diagnostic tools. We are dedicated to providing unparalleled service, ensuring the ongoing reliability and performance of your vehicle. There’s no need to delay any further. Take the first step by booking an appointment with us today.