Check Engine Light: What It Looks Like and What It Means

As a general safety feature, all cars or light trucks include an onboard diagnostic (OBD) system. When this system senses mechanical failure, it often illuminates the “check engine” light to notify the driver that the vehicle needs attention.

But, when this does happen, the dashboard isn’t able to tell you what caused the malfunction—just that you need to look into it.

So why is your check engine light on? We’ll walk you through what that looks like, as well as the five most common causes that explain a check engine light meaning for any vehicle.

What Does the Check Engine Light Look Like?

The check engine light will be on your dashboard (or "instrument cluster") behind your steering wheel when you sit in the driver’s seat of your car. It may look like a small engine or may say “CHECK ENGINE” or “SERVICE ENGINE SOON.” You may notice a yellow check engine light, red engine light, or other colors as well. This same light could be solid or flashing, depending on the severity of your engine issue.

Can Low Oil Cause a Check Engine Light?

Yes, low oil can trigger a warning, though it’s not always the first sign. Since the OBD system can’t measure oil levels directly, the check engine light meaning here usually comes from related issues such as low oil pressure or damage to engine components caused by a lack of lubrication.

If your check engine light is on and you suspect low oil, check the dipstick right away. Driving with too little oil can lead to serious damage that even an extended warranty may not fully cover if neglect is involved.

What to Do When the Check Engine Light Comes On

Sometimes you might not even need to look at the check engine light to know something is wrong with your car. You could be able to tell something is up based on some pretty clear conditions, such as your engine not turning on. However, when problems are not as obvious, deciphering your check engine light’s meaning will be the first indicator that you’ve got a problem.

Before we talk about some possible check engine light causes, there are a few things to consider in order to determine your next steps.

Is the Check Engine Light Flashing or Solid?

When you notice your check engine light is on, take note of whether or not the light is solidly on or if it is flashing on and off. If you see a solid check engine light, then that’s your OBD system telling you that there’s an engine issue.

However, if you see your check engine light flashing, you should calmly pull over at the next safest location to see what’s going on.

If you’re in that scenario, it will be helpful to call any roadside assistance you have on hand. If you have a plan through CarShield, for example, your coverage automatically includes 24/7 roadside assistance and towing, as well as rental car options.

So, until your check engine light turns off or resets, CarShield administrators will be there for you to help you through the process of fixing your covered repair.

How Does the Drive Feel?

Once you see that check engine light on, take a quick assessment of how your car drove when it turned on. Is the car driving normally, or did your speed suddenly drop? Or did you start hearing a concerning rumble from the engine?

Take note of any significant changes to your driving experience. Then, let your mechanic know about any of these observations.

As a side note, your check engine light may illuminate when your car simultaneously activates a “limp mode.” When that happens, your car will cap your speed and turn off power for any unnecessary accessories so that your car at least has a chance to hobble home in its “injured” state.

Some cars are built with this mode included to minimize further vehicle damage. That also counts as a safety feature! It won’t be helpful if your car experiences mechanical issues while you’re cruising at 70 mph with no clue that your car is starting to fail.

What Does the Check Engine Light Mean?

Unfortunately, as we mentioned before, the check engine light can only tell you that there is a problem—it cannot tell you what that problem is. There are, however, a few common causes for the check engine light to be on. Below, we’ll talk about the reason a check engine light comes on.

Possible Problem What Is the Check Engine Light’s Meaning in This Scenario? 1 Malfunctioning (or Missing) Catalytic Converter A catalytic converter protects the environment by converting carbon monoxide from your engine into carbon dioxide. Without this car part, your car probably can’t pass emissions tests. Catalytic converter malfunction may be a contained issue, or it may have been caused by the failure of a related car part. 2 Broken Oxygen Sensor Your car needs a specific amount of oxygen and fuel to function efficiently. Oxygen sensors in your vehicle measure how much O2 is left in the exhaust gases exiting your engine. If this sensor picks up on too much or too little oxygen in the exhaust gas, it will send signals to another part of the engine to adjust how much fuel is being allowed into the engine cylinders. 3 Ignition Coil or Spark Plug Problems Your car needs continuous controlled “explosions” to generate the necessary power to move. The ignition coil takes low-voltage electricity from your battery and converts it to high-voltage energy. That converted energy is delivered to the spark plugs so they can ignite the fuel needed for engine combustion. When either of these parts stop working, your car can’t start. 4 Mass Airflow Sensor Issues Your mass airflow sensor (MAS) determines the correct air-fuel mixture needed to run the engine by measuring how much air is entering the engine. If this part fails or gets too dirty, it may not be able to identify the appropriate amount of required gas. 5 Loose or Faulty Gas Cap That little screw-on cap for your gas tank may be more important than you think. Aside from keeping gas in your tank, it also prevents gas from evaporating and helps your fuel system circulate properly. Due to its importance, if your car senses a problem with that gas cap, it may turn the check engine light on.

What Happens if I Ignore My Check Engine Light?

If your car still seems to run ok while showing a check engine light alert, do still remember to investigate the cause of the check engine light. Ignoring it could seriously damage your car or cause your car to use up more fuel than it needs to. Even if you’re still able to drive your car, it’s possible that your vehicle is only getting more and more damaged as you drive it.

Additionally, if you don’t take care of a known issue with your car, certain conditions of an insurance policy or vehicle service contract may be voided. That means that, if you don’t address car issues in a reasonable manner, your protection plan may not cover certain repairs for your car.

Finally, if your check engine light is on, your car may not pass a car inspection or emissions test when you are required to have one. That can create an additional headache for you at a time when you would have preferred to avoid extra repair charges.

How to Turn Off the Check Engine Light

Before you try to turn off your check engine light, make sure you do everything you can to find out the cause of the issue. It is not advisable to try to turn it off without fixing the problem first. Doing so could cause additional damage to your car or, worse, could eventually endanger you and people driving around you.

When the issue is resolved and you’re ready to turn off the check engine light, then you should consult your owner’s manual or your local mechanic for the steps to reset your check engine light. Steps to turn off a check engine light may be different depending on the year, make, and model of your car.

How to Fix Check Engine Light Issues

Fixing a check engine light starts with identifying the cause. While some issues are simple, others require professional repair. Here are 5 critical steps to take:

1. Check and tighten your gas cap, a common culprit.
2. Inspect oil levels and top off if they’re low.
3. Look for visible problems like loose battery cables.
4. Use an OBD-II scanner to read stored error codes.
5. Schedule a diagnostic with a mechanic if the light stays on.

Once repairs are complete, the light can be reset. Staying proactive with maintenance and your auto protection helps avoid costly repairs. Learn more by contacting us at CarShield.

Check Engine Light On? Plans Through CarShield May Help.

No matter when your check engine light surprises you, you’ll be glad that you have a vehicle service plan through CarShield. After using the complimentary 24/7 roadside assistance, towing, and rental car options while your car is in the shop, our administrators will be able to help you with the bill for your covered repair. Not only that, but CarShield members can enjoy a variety of other benefits with their vehicle protection coverage! Call the number or click the “GET FREE QUOTE” button at the top of this page to get started!