Why Is My Check Engine Light On? — Don't Ignore

The lights on our dashboards are all useful, but none cause as much concern as the check engine light. When it turns on, it’s often a harbinger of expensive repair work. Though it appears simple, the check engine light is actually quite sophisticated. It works like this: when something goes wrong in your vehicle, it attempts to repair itself in any way it can. When it can’t self-correct, the car turns on the warning indicator light to alert the driver that there’s a problem. It also stores a specific code in its memory to better identify the problem. Your mechanic can read this code using a diagnostic computer.

While the check engine light is on, your car will try to compensate for the problem at hand. Because of this, you may not notice the vehicle running any differently than usual. However, the reality is that your fuel economy will likely suffer, and your vehicle’s emissions may increase if the issue triggering the engine light goes unchecked. In some cars, a flashing check engine light indicates a serious problem that needs immediate attention. Regardless of whether the light is flashing, ignoring the check engine light is never a good idea.

Why Is My Check Engine Light On?

All the warning lights on your dashboard tell you that something needs your attention. The first thing you need to do is find out if it’s the check engine light or a service light. A maintenance or service light simply means that it’s time for routine work, such as an oil change or tire rotation. Maintenance or service lights can look slightly different on every vehicle. The best place to find out which light is on and what it means is to consult your owner’s manual. It will show you a picture of your check engine light and other dashboard symbols.

Common Check Engine Light Errors

Let’s consider the most common answers to the eternal question, “Why is my check engine light on?”

Lost or Missing Gas Cap

A missing or damaged gas cap is a common reason for a check engine light. The gas cap plays a crucial role in maintaining the proper pressure in your fuel system by preventing fuel vapors from escaping into the atmosphere. Fortunately, the fix is simple. Tighten the cap or replace it if it is missing or does not make a good seal.

Bad Oxygen Sensor

Another possible reason your check engine light is on is a bad oxygen sensor. The oxygen sensor monitors the oxygen levels in your car’s exhaust, helping to manage the engine’s fuel-to-air ratio. When this sensor fails, your car’s fuel economy suffers, increasing emissions and potentially damaging engine components such as the catalytic converter. Replacing a bad oxygen sensor is essential to maintaining your vehicle’s performance and preventing costly repairs.

Emission Problems

The check engine light may also indicate broader emission problems related to the catalytic converter or the exhaust gas recirculation (EGR) valve. These parts help reduce harmful emissions, ensuring your vehicle meets environmental standards. An issue with your emission system negatively impacts your car’s performance and may cause it to fail your next emissions test, which may needed to renew your registration.

Engine Problems

Of course, the most severe check engine light alerts refer to engine problems. The issues range from minor malfunctions like a faulty spark plug to more significant concerns such as misfires, overheating, or even engine failure. However, even “minor” engine issues can become serious. Worn-out plugs will hinder the process of combustion, making misfires more likely. A misfire when you’re trying to accelerate on the highway could make for a deadly malfunction, so don’t wait until the spark plugs and wires are completely worn out to replace them.

When the engine light is triggered by poor engine performance, prompt action is vital. Ignoring this critical warning sign can leave you stranded on the side of the road with severe damage requiring costly repairs.

Is the Check Engine Light Serious?

The next thing you may be wondering is if the check engine light is serious. Many cars have several flash sequences that can give you a clue as to what is wrong. As we saw above, several common problems can trigger a check engine light. Another potential problem source is with the modules and sensors that control the powertrain. Issues with the air filter, fuel delivery, or ignition systems can all trigger the light.

All the problems that could trigger a check engine light are serious. If the check engine light comes on, it’s one dashboard light you should not ignore. If ignored, your vehicle, and by extension, your personal safety, is at risk. Because your vehicle cannot alert you to new or worsening problems, small problems can quickly morph into large ones. Since the engine light is already on, there’s no way for your car to tell you about other issues that might crop up, either.

What To Do When the Check Engine Light Comes On

There’s no need to assume the sky is falling and immediately pull over when your check engine light comes on. Instead, make a point to see a mechanic as soon as is reasonably possible. Just double-check your gas cap first — it’s such an easy fix.

Start by removing your gas cap completely and replacing it as you normally would. Take your car for a test drive to see if the light turns off. It may take several miles or several restarts of the car for the light to flicker off. If the engine light remains lit, consider getting a new gas cap. Purchase one made specifically for your car model and replace the old cap. If your light still does not turn off, take your vehicle to a garage for a full diagnostic.

Your car is likely one of your biggest investments, so it makes sense to maintain it regularly. By taking the check engine light seriously, you can keep repair costs to a minimum. Staying proactive helps you avoid accidents, breakdowns, and over-the-top bills from your local mechanic.

When Maintenance is Needed

When replacing your gas cap doesn’t resolve the check engine light, take your car to a professional mechanic you trust. You don’t need the hassle and costly repairs that ignoring the light can cause. Regular maintenance, such as timely oil changes, replacing worn belts, and addressing the engine light, keeps your car running at its best and extends its lifespan.

Diagnosing the Problem of Check Engine Light

When your check engine light comes on, it does so in response to a detailed issue. To learn whether it is pointing to a bad oxygen sensor, emission problems, or other issues, your auto mechanic will connect a code scanner under the dash to download the coded information from your car’s onboard computer and translate it. The diagnostic trouble codes (DTCs) provide valuable information about what’s causing the engine light to illuminate.

While professional mechanics have the tools and training to interpret the DTCs and resolve them, there are code scanners designed for car owners on the market. Using one will give you insight into why the check engine light went on. But you may still need a pro to make the necessary repairs.

Wawanesa Insurance wants you to stay safe, so we recommend taking care of a check engine light as soon as it comes on. Contact us for any of your car insurance needs or questions about coverage. While mechanical breakdowns and failures aren't eligible for insurance coverage, Wawanesa can help with all kinds of other auto disasters. Prepare for what may lie ahead with a free quote for auto insurance. You can get one right now on our website. It’s quick, easy, and less stressful than any check engine light, we promise!