A new light on your dashboard? You don’t figure out why it doesn’t shut off… It’s typical, a car is complex and there are various reasons why a light could come on. If it turns out your glow plug light comes on while driving your Volkswagen Passat , it might reveal some issues. In this post, we will do everything we can to help you see things more clearly. First, we will see how the preheating light on your Volkswagen Passat operates, and then the different explanations it lights up when you are driving


What is the purpose of my Volkswagen Passat glow plug light?

The main intent of the engine glow plug light, which is generally symbolized by a yellow coil, is to make sure that your glow plugs are working properly. Indeed, it must light up when you switch on your Volkswagen Passat to tell you that they are heating the intake air in your cylinders and must go out after a few moments 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 detail the main ones.

What to do if the glow plug light comes on while driving on my Volkswagen Passat ?

A glow light that comes on while driving on your Volkswagen Passat 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 look at this right now. No matter the reason, connecting your vehicle to the diagnostic tool will allow you to carefully understand the cause for the light up of your glow light.

My Volkswagen Passat glow light comes on and I’m going through a loss of power

The first probability is that you perceive that your glow plug light comes on while driving your Volkswagen Passat and that you also experience a loss of power. In this instance, some trouble can demonstrate its lightning. Here is a list of the main reasons:

  • Trouble of EGR valve, indeed, if you are affected a loss of power, it is possible that your EGR valve is blocked, in this instance, it is obvious that your preheat light comes on while driving on Volkswagen Passat because it is one of the failures of which it is designed to warn you. Have the status of your valve looked at
  • Problem 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 operation of the turbo.
  • Problem associated with the injection, either an injector that has seized up or the injection pump that is damaged by filings or other possible foreign bodies that disturb its proper function.
  • Finally, the last trouble that could lead to a glow indicator light on your Volkswagen Passat 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 Volkswagen Passat

To conclude, we’ll give you the explanations for a glow plug light that comes on on your Volkswagen Passat without you feeling any difference in power or motor vehicle behaviour. Generally, 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 solve the trouble.
  • You have a false contact somewhere in your electrical circuit, check the other solutions first because it is not easy to find it alone, we advise you to go to your mechanic.
  • Faulty injection pressure sensor, ECU error
  • To find more tips on the Volkswagen Passat , take a look at the Volkswagen Passat category.