Mercedes Repair Shop – Why Your Engine Warning Light Is On

For many of us, cars are an important part of our daily lives. They drive us to work, to school, to wherever we need to be, and back again. It is therefore quite understandable that the sight of a flared up “check engine light” is often the cause of great worry and concern. Although it is recommended that if the light goes on, you contact a reputable repair service (such as Mercedes repair shop), knowing the possible causes of the light going on can often help with allaying worries.

What Is A Check Engine Light?

The check engine warning light or “check engine light” is a tell-tale used by computerized engine-management systems. It is a light (usually found in the instrument panel) which when lit up (usually) means that there is a malfunction.

Why Is It On?

As mentioned above, the light usually illuminates when there is a malfunction. Common causes of it lighting up include:

1. Faulty Oxygen Sensor

   Oxygen sensors monitor the amount of oxygen from the exhaust which is unburnt. It may become faulty due to the sensor becoming covered in oil ash. The result of this is incorrect data, reduced ability to change oxygen and fuel mixture which will reduce gas mileage and increase emissions. Faulty sensors are easily replaced by unclipping the old sensors and replacing them with new ones.

2. Loose Or Faulty Gas Cap

   Loose gas caps may be a result of not being tightened properly or being cracked/damaged in other ways. This may cause fuel vapors to leak and throw the fuel system off. It can also cause reduced gas mileage and increased emissions. This is rectified by tightening or replacing the damaged fuel cap.

3. Faulty Catalytic Converter

   Catalytic converters change carbon monoxide and other damaging gases into harmless compounds. When this is failing, your car may struggle to accelerate when you push the gas and there may be a decrease in gas mileage. Failure is usually related to other items such as broken oxygen sensors. If failing, you should replace the catalytic converter as soon as possible as it will decrease gas mileage and the car may stop running completely.

4. Faulty Mass Airflow Sensor

   This tells the car how much fuel to add based on the amount of air coming through the engine. If the mass airflow sensor stars to fail, it is essential that it is replaced as soon as it is diagnosed. This is important because a failing or faulty airflow sensor can cause a variety of issues such as the car stalling, decreased gas mileage, increased emissions, and car failure. The most common reason for failure is due to air filters (which should be replaced around once a year) being incorrectly installed or replaced. A faulty mass airflow sensor is fixed by replacing it.

5. Spark Plugs And Wires

   Spark plugs provide seals for the combustion chamber and allows a spark to jump across it. They help also start combustion in the engine. When spark plugs fail you will often notice it as a jolt or jump in your car’s acceleration. Spark plugs often fail over time with pre-1996 vehicle spark plugs needing to be replaced every 30 000 miles and newer vehicle spark plugs lasting up to 100 000 miles. If they are faulty then they should be replaced immediately.

In short, there are a variety of reasons why the check engine light may come on from oxygen sensors to spark plugs. Although many are relatively simple to rectify it is best to book your vehicle in with a bona fide vehicle service and repair workshop, such as our Mercedes repair shop, in order to have a quality job performed and peace of mind that it was done correctly.