A new light on your dashboard? You don’t understand why it doesn’t shut off… It’s normal, an automobile is complicated and there are multiple causes why a light could occur. In the event that your glow plug light comes on while driving your GMC Sierra, it might show different issues. In this article, we will do everything we can to help you see things more clearly. First, we will see how the preheating light on your GMC Sierra works, and then the different explanations it lights up when you are driving

glow-plug-light-gmc-sierra

What is the purpose of my GMC Sierra glow plug light?

The main goal of the engine glow plug light, which is in most cases represented by a yellow coil, is to make sure that your glow plugs are working correctly. In reality, it must light up when you switch on your GMC Sierra 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 vehicle. But, if it turns on while driving, it may suggest several troubles, we will try to describe the main ones.

What to do if the glow plug light comes on while driving on my GMC Sierra?

A glow light that comes on while driving on your GMC Sierra or at any other time other than when the engine is started is intended to alert you to a fault other than your spark plugs, we will take a look at this right now. No matter the reason, connecting your vehicle to the diagnostic tool will allow you to precisely understand the reason for the light up of your glow light.

My GMC Sierra glow light comes on and I’m going through a loss of power

The first possibility is that you recognize that your glow plug light comes on while driving your GMC Sierra and that you also encounter a loss of power. In such a case, different complications can explain its presence. Here is a list of the main causes:

  • Issue of EGR valve, in fact, if you suffer a loss of power, it is possible that your EGR valve is clogged, in this case, it is expected that your preheat light comes on while driving on GMC Sierra because it is one of the problem of which it is meant to alert you. Have the status of your valve looked at
  • Problem related to the turbo overflow valve, in this situation the ECU can no longer manage the turbo intake pressure, which can result in turbo boost and a perturbation in the performance of the turbo.
  • Problem relevant to the injection, either an injector that has seized up or the injection pump that is damaged by filings or other possible foreign bodies that disrupt its proper performing.
  • Finally, the last trouble that could lead to a glow indicator light on your GMC Sierra coupled with a loss of power, is that your fuel filter is too dirty, you should get 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 GMC Sierra

Finally, we’ll give you the explanations for a glow plug light that comes on on your GMC Sierra without you feeling any difference in power or vehicle behaviour. In most cases, this is an electronic fault:

  • Glow plug relays or fuses to be replaced, test and change 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 alternatives first because it is not easy to find it alone, we encourage you to go to your technician.
  • Faulty injection pressure sensor, ECU error

    • To get more tips on the GMC Sierra, take a look at the GMC Sierra category.