Why Does the Check Engine Light Come On?
The Check Engine Light – that small, seemingly innocuous dashboard warning that can send shivers down the spine of any vehicle owner. We’ve all seen it, that little orange or yellow symbol that suddenly lights up and leaves us wondering, “What’s wrong with my car?”
In this guide, we will delve into the world of the Check Engine Light, its significance, the common reasons behind its activation, how to interpret Check Engine Light codes, and the steps to diagnose and address the underlying issues. Armed with this knowledge, you’ll be better equipped to make informed decisions about your vehicle’s health.
What Does the Check Engine Light Mean?
The Check Engine Light, AKA Service Engine Soon Light, is a signal sign on the dashboard that indicates issues detected in the vehicle. It’s part of the vehicle’s Self Diagnostic function and a signal that a problem is detected by the vehicle computer. It’s essentially your car’s way of communicating with you. When this light illuminates on your dashboard, it’s indicating that the Engine Control Unit (ECU) has detected a problem or irregularity in one or more of the many systems it monitors.
It’s essential to understand that the Check Engine Light (CEL) doesn’t pinpoint the exact issue. Instead, it serves as a general warning sign that something is amiss. To get to the root of the problem, you’ll need to perform a diagnostic scan using a code reader to retrieve specific trouble codes. It generally indicates the direction you need to take to get to the bottom of your symptoms. The vehicle has an innate self-diagnostic system and does checks frequently. When the vehicle computer, Powertrain Control Module, detects problems, it will ignite the check engine light to send a message.
However, there’s one thing for sure: it doesn’t come on for no reason, but most of the time, the problems might be minor, and you just don’t feel anything off.
The Top 5 Reasons Your Check Engine Light May Activate
The causes behind a Check Engine Light activation can vary widely, but some common culprits include:
Loose or Faulty Gas Cap
Your gas cap is part of a sealed evaporative emissions system that recirculates gasoline vapors from your gas tank and keeps them from escaping into the air. Because of this, this system of lines and valves is closely monitored, and one of the key sealing pieces of this is the gas cap.
If you leave your gas cap off accidentally, it won’t take long before the diagnostic system sets Check Engine Light codes. These leaks in the EVAP emission control system are often grouped as “small” or “large” leaks. It’s important to note that the problem is not always the gas cap, but could be one of the plastic recirculation lines, fittings, or connectors causing the leak, but often the gas cap is the culprit.
What happens if I don’t replace it?
- You can lose fuel through evaporation.
- Your recirculation system will not function properly.
- You will have to stare at the CEL until it’s fixed.
Oxygen Sensor Issues
Your oxygen sensor measures the amount of unburned oxygen in your vehicle’s exhaust system. It indicates how thoroughly the air-fuel mixture burned during the combustion process. Oxygen sensors also live a hard life in +800-degree exhaust temps and are prone to fail over 80,000 miles or more.
What happens if I don’t replace it?
- Your engine will burn more fuel than needed.
- You will lose fuel economy and get fewer miles per gallon.
- Faulty sensor(s) can cause damage to your spark plugs and catalytic converter.
Engine Misfires
If your car is misfiring, you probably aren’t wondering to yourself “Why is my check engine light on?” Your spark plugs ignite the air/fuel mixture in the combustion chamber of your vehicle, but if the timing of that spark, the mixture of the fuel and compression of the mixture isn’t perfect, you will get a misfire. Multiple issues can cause a misfire, either on one cylinder or a multiple cylinder misfire.
What happens if I don’t replace it?
- You will experience poor performance (reduced power, engine missing) and reduced fuel economy.
- The misfire will only get worse and will lead to mechanical failure in the engine.
Mass Ari Flow Sensor (MAF) Troubles
Your mass airflow sensor (MAF) measures the amount of air entering the engine to determine how much fuel is needed to run your engine properly. If there are any leaks before or after the mass airflow sensor in the intake tract, a light can trigger. Mass airflow sensors are sensitive to oil, dirt, and water vapor, and any contamination on them can trigger a light. Sometimes, cleaning the sensor with intake or mass airflow sensor cleaner can fix the issue. Other times, the sensor needs to simply be replaced. Be sure to check the intake ducting carefully for leaks, rips, or damage.
What happens if I don’t replace it?
- A faulty MAF sensor can cause rich or lean conditions, which can lead to further failures of other parts.
- You will experience reduced performance and fuel economy.
Catalytic Converter Issues
Your catalytic converter helps protect our environment by superheating hydrocarbons and other harmful tailpipe emissions into compounds like carbon dioxide and water vapor. Your downstream oxygen sensors carefully monitor the converter’s performance, and if something goes awry, several trouble codes based on “Catalyst efficiency” will appear.
It’s important to note that a catalytic converter will more than likely not fail on its own. Generally, something causes it to fail or not perform properly. Because of this, simply replacing the converter or the oxygen sensors around it will often not fix the problem, and often leads to yet another failed converter. Things as serious as a blown head gasket can force burned coolant vapor into the exhaust, triggering a catalyst engine code.
What happens if I don’t replace it?
- Your vehicle will not pass an emissions test.
- You will experience reduced performance and fuel economy.
- Whatever caused the converter to fail initially will continue to get worse, possibly causing engine failure.
Consequences of Ignoring the Check Engine
Ignoring the Check Engine Light is not a wise choice. Here’s why:
Decreased fuel efficiency
Many issues that trigger the Check Engine Light can reduce your vehicle’s fuel efficiency, costing you more at the pump.
Increased emissions
A poorly performing engine can produce higher emissions, contributing to environmental pollution.
Escalation of problems
What might start as a minor issue can escalate into a major, more expensive problem if left unaddressed.
Safety concerns
In some cases, the Check Engine Light can illuminate due to safety-related issues, such as a faulty airbag system or braking system. Ignoring these warnings can compromise your safety on the road.
Tips For Preventing Unnecessary Check Engine Light Activations
While not all Check Engine Light activations can be prevented, you can take steps to reduce the likelihood:
Regular maintenance
Follow your vehicle’s recommended maintenance schedule, which includes oil changes, air filter replacements, and spark plug checks.
Tighten the gas cap
After refueling, make sure to tighten the gas cap securely to prevent evaporation of fuel vapors.
Drive responsibly
Avoid aggressive driving, which can strain your engine and lead to premature wear and tear.
Use quality fuel
Choose reputable gas stations and use quality fuel to maintain your engine’s health.
The Check Engine Light is your car’s way of alerting you to potential issues. Understanding its significance, interpreting the codes it generates, and taking appropriate action can save you time, money, and stress in the long run.
Lest Us Help You Figure Out The Problem, Take Your Vehicle to Groovy Lube
The most convenient way to clear check engine light is to take it to a mechanic at Groovy Lube. Our mechanics will conduct a car inspection on the vehicle and fix all the problems, and then the check engine will go off.
