A new warning light on your dashboard? You don’t figure out why it doesn’t switch off… It’s typical, an auto is elaborate and there are many factors why a light might come on. If it turns out your glow plug light comes on while driving your Audi S4, it may possibly signal different concerns. In the following paragraphs, we will do everything we can to help you see things more clearly. First, we will discover how the preheating light on your Audi S4 operates, and then the different motives it lights up when you are driving

glow-plug-light-audi-s4

What is the goal of my Audi S4 glow plug light?

The primary role of the engine glow plug light, which is most of the time represented by a yellow coil, is to ensure that your glow plugs are working correctly. Indeed, it must light up when you switch on your Audi S4 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 meant to stay or come on while driving with your motor vehicle. Nevertheless, if it comes on while driving, it may indicate several issues, we will try to explain the main ones.

What to do if the glow plug light comes on while driving on my Audi S4?

A glow light that comes on while driving on your Audi S4 or at any other time other than when the engine is started is meant to alert you to a fault other than your spark plugs, we will take a look at this right now. In any case, plug in your car to the diagnostic tool will allow you to precisely interpret the reason for the light up of your glow light.

My Audi S4 glow light comes on and I’m going through a loss of power

The first probability is that you notice that your glow plug light comes on while driving your Audi S4 and that you also experience a loss of power. In such a case, different problems can demonstrate its presence. Here is a list of the main factors:

  • Issue of EGR valve, in fact, if you undergo a loss of power, it is possible that your EGR valve is clogged, in this instance, it is obvious that your preheat light comes on while driving on Audi S4 because it is one of the problem of which it is expected to notify you. Have the status of your valve checked out
  • Issue linked to the turbo overflow valve, in this situation the ECU can no longer manage the turbo intake pressure, which can lead to turbo boost and a disturbance in the performance of the turbo.
  • Issue linked to the injection, either an injector that has seized up or the injection pump that is broken by filings or other possible foreign bodies that affect its proper performing.
  • Finally, the last problem that could lead to a glow indicator light on your Audi S4 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 Audi S4

To conclude, we’ll give you the motives for a glow plug light that comes on on your Audi S4 without you feeling any difference in power or motor vehicle behaviour. In most cases, this is an electronic fault:

  • Glow plug relays or fuses to be changed, 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 fix 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 mechanic.
  • Faulty injection pressure sensor, ECU error

    • To discover more tips on the Audi S4, take a look at the Audi S4 category.