Check engine light illuminated....time to take it in for maintenance and repair!
Photo Credit: Andrew Huff
You’re cruising down the road and all of a sudden you hear a dash noise and see the check engine light illuminate on your dashboard. What does this mean? What do I do? First, don’t panic.
The check engine light (CEL) comes on in your vehicle to let you know that your Mercedes-Benz’s onboard diagnostics system has detected an issue. This may be to warn you that you need some upcoming routine maintenance. It might be something small and easy to fix, or it might be more complex (generally if it’s flashing). Let’s take a look at some of the common causes as to why the check engine light may turn on and steps to take.
Loose or Faulty Gas Cap - Check if the gas cap is loose or damaged. Tighten it and see if the light turns off again.
Oxygen Sensor Failure - The oxygen sensor measures the amount of unburned oxygen in the exhaust system. A faulty sensor can affect fuel economy and emissions.
Catalytic Converter Issues - The catalytic converter helps reduce exhaust emissions. Problems here can cause the CEL to come on and lead to reduced performance.
Mass Airflow Sensor (MAF) Problems - The MAF sensor measures the amount of air entering the engine. A failing MAF sensor can cause engine performance issues.
Spark Plugs and Wires - Worn spark plugs or bad spark plug wires can cause misfires, impacting engine performance and triggering the CEL.
Faulty Ignition Coil - The ignition coil converts the battery's voltage to a higher voltage needed to create a spark in the spark plugs. A bad coil can lead to misfires and poor engine performance.
Exhaust Gas Recirculation (EGR) Valve Issues - The EGR valve recirculates a portion of the exhaust gases back into the engine cylinders. Problems with the EGR valve can affect emissions and engine performance.
Vacuum Leaks - Vacuum leaks can occur in various places, such as the intake manifold gasket, vacuum hoses, or the throttle body, leading to the CEL coming on.
Faulty Fuel Injectors - Fuel injectors deliver fuel to the engine's cylinders. Issues with the injectors can cause the engine to run lean or rich.
Battery or Charging System Problems - Issues with the battery or alternator can trigger the CEL.
Now I Know What An Illuminated CEL Could Be, What Do I Do Next?
If nothing else is illuminated on your dash and there are no obvious signs of trouble or performance issues, safely pull over and check that the gas cap is tightened and look under the hood. Obvious issues under the hood would be loose or disconnected wires and hoses.
*It’s a good idea to take a look at your owner’s manual, which may provide specific guidance on what to do when the CEL comes on.
If everything appears normal and your CLE is still illuminated (or flashing), take it to get to a professional Mercedes-Benz repair mechanic. They will be able to run diagnostics which will identify the problem(s), and be able to fix it for you.
Find a qualified Mercedes-Benz repair shop to perform routine brake maintenance on your Mercedes-Benz today!