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Top 5 Reasons Your Check-Engine Light is On

Top 5 Reasons Your Check-Engine Light is On

We’ve all been there, a little yellow illumination catches your eye as you drive, the dreaded Engine light has turned on. If you’ve been here many times before, you probably let out an audible sigh and think about when you will bring your car in to get scanned to find out what is wrong or contemplate letting that annoying reminder of your negligence simply linger. If this is new to you, you might even feel a little panic, “what do I do if my Check-Engine light is on?”.


Quick Tip: warning lights on your dashboard that are yellow are indications that something should be checked at an earliest convenience - they are not emergencies and do not warrant pulling off the road or extreme concern/caution while driving. However, if the yellow light is flashing, it should be considered time sensitive and treated immediately.


Yellow Engine Light


Red warning lights, especially those that are flashing, do constitute an emergency and you should find a safe place to pull off the road, turn off your vehicle and call for assistance (or of course take appropriate action yourself if you are well versed)


engine light


Either way, you are definitely thinking, “why is my engine light on”?


While the Check-Engine light can be on for a variety of different reasons, they are typically related to emission components of your vehicle. Therefore, as a general rule, your check-engine light is not an emergency, although it is something that will impact your fuel economy and the performance of your vehicle. Many of the initial causes for your light being triggered can cause a domino effect if left untreated - so while there’s definitely no reason for panic, addressing the cause is important.


Your best bet to find out exactly what triggered your check-engine light is to have it scanned using a Engine Fault Code Reader - this is something one of our Service Advisors can assist you with, contact us here to set-up an appointment. In the meantime, here are the most likely culprits for why your check-engine light is on:


  1. Gas cap is not on correctly (or is broken/damaged) - this is the absolute first thing you should check if your engine-light comes on. A loose or broken/damaged cap causes the warning light to be triggered because vapours are escaping. This tends to be the least expensive fix for an engine light - either free (just tighten the cap) or the cost of replacing the cap (which depends on your vehicle)
  2. O2 Sensor - your oxygen sensor (aka O2 sensor) lets the computer know if the fuel mix is burning rich (not enough oxygen) or lean (too much oxygen) and dynamically adjust accordingly. When an O2 sensor stops working, the engine-light will come on so you know it requires replacement
  3. Catalytic Converter - the system that uses a chemical reaction to clean the toxic gases from your engine, can get clogged, damaged or broken - usually due to another underlying issue or age. While one of the less frequently causes of your engine light going on, it is typically the most expensive to fix/replace
  4. Ignition coils and/or spark plugs - your spark plugs ignite the fuel in your vehicle’s combustion chamber - they get their spark from the ignition coil. If any component of the spark plug/ignition coil is malfunctioning not only will your engine light go on, you will also likely notice a loss of power, slow acceleration, poor fuel economy, engine misfiring and even difficulty starting your car
  5. Mass airflow sensor - determines the mass of air that is entering your vehicle’s fuel injection engine and sends this information to your vehicle’s computer so that it can regulate. When this sensor is faulty, you may notice engine hesitation, stalling or difficulty starting your vehicle


How to reset the check-engine light?


Diagnosing the problem and correcting it will reset your check-engine light. You can also use an Engine Fault Code Reader/Scanner to reset the light manually - however if the issue causing the warning to be triggered has not been solved, the light will reappear.


At CarHub we are committed to your vehicle performance and safety. If you have any concerns, don’t hesitate to reach out to us. We’ll be happy to look into it and see what might be causing the warning. If you have any more questions about your check-engine light and/or your vehicle’s maintenance, just reach out to us. Let one of our Service Advisors guide you - contact our service department.

-Sharon Pinfold-
Sharon has been in the auto industry since 2005 and has worked both in the Sale and Service Department of various New, Used, Domestic and Import brands.

Categories: Service & Maintenance Tips