A new light on your dashboard? You don’t understand why it doesn’t turn off… It’s normal, a vehicle is elaborate and there are multiple factors why a light may occur. In cases where your glow plug light comes on while driving your Mercedes Classe S, it might point out different problems. In the following paragraphs, we will do anything we can to support you see things more clearly. First, we will find out how the preheating light on your Mercedes Classe S functions, and then the different motives it lights up when you are driving

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What is the purpose of my Mercedes Classe S glow plug light?

The primary intent of the engine glow plug light, which is generally represented by a yellow coil, is to assure that your glow plugs are working correctly. In fact, it must light up when you switch on your Mercedes Classe S to tell you that they are heating the intake air in your cylinders and must go out after a few minutes when the engine is running. This preheat light is therefore not supposed to stay or come on while driving with your car. Nevertheless, if it turns on while driving, it may indicate multiple failures, we will try to summarize the most important ones.

What to do if the glow plug light comes on while driving on my Mercedes Classe S?

A glow light that comes on while driving on your Mercedes Classe S or at any other time other than when the engine is started is intended to inform you to a fault other than your spark plugs, we will take a look at this right now. No matter the reason, a switch to the diagnostic tool will allow you to properly translate the reason for the light up of your glow light.

My Mercedes Classe S glow light comes on and I’m suffering from a loss of power

The first probability is that you perceive that your glow plug light comes on while driving your Mercedes Classe S and that you also knowledge a loss of power. In this instance, different trouble can describe its lightning. Here is a list of the most important factors:

  • Issue of EGR valve, in fact, if you are affected a loss of power, it is possible that your EGR valve is clogged, in such a case, it is logical that your preheat light comes on while driving on Mercedes Classe S because it is one of the problem of which it is meant to alert you. Have the status of your valve checked out
  • Problem associated with the turbo overflow valve, in this situation the ECU can no longer control the turbo intake pressure, which can cause turbo boost and a perturbation in the operation of the turbo.
  • Problem linked to the injection, either an injector that has seized up or the injection pump that is destroyed by filings or other possible foreign bodies that disturb its proper performing.
  • Finally, the last problem that could lead to a glow indicator light on your Mercedes Classe S coupled with a loss of power, is that your fuel filter is too dirty, you should experience jerks because of a bad fuel flow in the engine.

My glow plug light comes on or is flashing but no difference on the performance of my Mercedes Classe S

To conclude, we’ll give you the motives for a glow plug light that comes on on your Mercedes Classe S without you feeling any difference in power or car behaviour. In most cases, this is an electronic fault:

  • Glow plug relays or fuses to be replaced, test and replace if necessary.
  • A contactor/potentiometer on one of your pedals (brake, accelerator or clutch) has failed, often a simple de-seizure will be enough to solve the problem.
  • You have a false contact somewhere in your electrical circuit, test out the other options first because it is not easy to find it alone, we suggest you to go to your auto mechanic.
  • Faulty injection pressure sensor, ECU error

    • If you wish more guides on the Mercedes Classe S, go to our Mercedes Classe S category.