What to Do When the Check Engine Light Comes On

Everything feels cool while you are cruising on the highway. Suddenly, the Check Engine light on your dash pops out of the blue. What to do when the Check Engine light comes on?

You can take your vehicle to the nearest car repair shop, whether it is a solid or blinking light. Several factors can activate the Check Engine Light. You will need a car mechanic to pinpoint and fix the problem.

When the Check Engine light of your car comes on, you should immediately stop it and have it examined by a competent car mechanic as soon as possible. It’s not okay to drive it still. If you need to call for a tow truck, then use your best judgment.

Read on and learn more about what you need to do if your vehicle’s check engine suddenly lights up while you are driving.

What to Do When the Check Engine Light Comes On

what to do when the check engine light comes on

If the Check Engine light on your dash suddenly turns on while driving your car, you must bring it to the closest car repair shop – whether it is a solid or blinking light. Any number of things could cause it.

But you need to stop your vehicle immediately. You should also bring your car, as soon as possible, to the nearest car repair shop so the mechanic there can look and check why the light is turned on.

One of the common reasons the Check Engine light turns on is a malfunctioning Oxygen sensor. There is no way you can check if this is the real reason. So, the best way is to bring your car to the closest car service shop so they can diagnose the exact cause.

You can turn off the Check Engine light once you have addressed the issue. So, if your car has any condition that caused this light to come on, you have to pinpoint the cause and fix it. Hopefully, this light will turn itself off.

How Do You Fix a Check Engine Light?

Check Engine light coming on is the first sign that your car is having trouble. This light is an essential tool that functions as a digital red flag to warn you that something is going wrong under your vehicle’s hood.

Can you still drive with the Check Engine light on? You can reset this light most conveniently if you still want to go to your destination.

However, it is better to take your vehicle to the nearest mechanic so they can have a look-see. At any rate, you can reset this light if you want to, and here’s how you can do it:

1. Take the Car to a Mechanic

Let’s hope that the Check Engine light will turn off by continuing to drive your car. This is possible, but as I’ve said, it is unsafe since you still don’t know what caused the warning light to turn on.

It is possible that your car’s ECU only needs to recycle a computer error that triggered the warning light. Once the ECU has cycled out the error code, the warning light will fade away. So, drive your car as generally as you do for three days.

Hope and pray that the light will go away. If it persists in illuminating your dash, you must take it to a mechanic you trust. They will be the right person who can determine and fix your problem.

However, you cannot resort to this tactic if the warning light is frenziedly blinking on and off. That indicates a more severe problem that needs attention at once.

2. Turn the Ignition On and Off

You can also try turning the ignition on and off and see if the warning light turns off. This action will force the car’s computer or ECU to its saved previous state through a reboot of the system. It’s like rebooting your laptop or desktop when it suddenly stops or is experiencing a problem.

Just insert the ignition key in the slot and turn it on for about 1 or 2 seconds. Then turn it off for another 1-2 seconds. Do these three or four times and see what happens.

If the warning light insists on staying on, you have an underlying problem that needs to be fixed before doing a Check Engine light reset.

3. Use an OBD2 Scanner

If, after trying the first two tactics and still the warning light won’t budge in its place, then it’s time for you to get an OBD2 scanner. This is a diagnostic tool used by car mechanics to examine the causes of problems that a vehicle is experiencing.

Some scanners are designed for DIY mechanics, and there are professional and more expensive scanners that experienced mechanics use.

You don’t need the professional type because your current issue is easy to diagnose. If you can borrow one from a friend mechanic, you don’t need to buy this type of scanner.

You can also download apps online that function like a basic car scanner. If you can download such an app, you can use it to diagnose your most typical car problems.

If you have the basic OBD2 scanner, follow the steps below:

  • Plug its connector into your car’s OBD port. This port’s usually located under the steering wheel column in most cars.
  • Turn the scanner on, and you will find the error code for the Check Engine warning light and every issue you find in your vehicle.
  • Once you can identify the cause of the problem and get it fixed, you can now remove the flag by using the ‘clear’ or ‘erase’ button in the scanner. Remember: you must select the cause of the problem before resetting the Check Engine warning light.
  • Additionally, even if you have identified the trouble code with an OBD scanner, it is more than likely that you will still need the services of a competent mechanic to fix the underlying issue. Knowing the cause of the trouble code is the first step in resolving this problem.

4. ECU Hard Reset Tactic

You will need a wrench to solve this problem using a hard reset. This method will require you to disconnect and then reconnect your car battery. By doing this, you are practically hard resetting the control unit of your car’s onboard computer.

ECU’s Function

The ECU uses the data it gathers while you are driving your car. It uses this data to properly configure the operation of everything in your vehicle, from the engine to the exterior lights.

It can configure your driving habits, track your idling RPMs, engine tolerances, and fuel consumption, and then save all this data in the system’s RAM. The ECU also stores diagnostic data, along with your error codes.

As you continue driving your car, the data stored will inevitably change now and then. It will also get corrupted. If that happens, it may produce errors.

So, if you suspect that the Check Engine warning light is caused by an error, by wiping the data clean, you may be able to erase or clear the code – which will cause the warning light to fade off.

5. Disconnect the Battery

In disconnecting the battery, disconnect the black or negative terminal first before disconnecting the red or positive terminal. After this, drain the residual current left on the battery’s electric cable by blowing the horn, turning the car lights on for about 30 seconds, or pressing the brake pedal.

After you’re done, reconnect the battery by connecting the red terminal before joining the black terminal. Start the engines as you typically do and see if this method resets the Check Engine light.

Again, what to do when the Check Engine light comes on? Take your car to a mechanic when the Check Engine light comes on. The mechanic will identify the problem and fix whatever causes the warning light to come on.

Static Vs. Blinking Check Engine Light

what to do if check engine light on

What about the difference between a solid and a blinking Check Engine warning light? There is a big difference between a flashing and a steady warning light. Here is the main difference between the two:

  • You must stop your car if it is a flashing or blinking warning light. It could be a severe problem. The solid warning light is an indication of an impending catastrophic problem.
  • If the warning light stays steady or solid without any movement whatsoever, then there’s no need for you to panic.

You must stop immediately if it’s the situation in your car. Ask for the assistance of a tow truck to bring your vehicle to the nearest car repair center. But if it’s the second situation, you can still complete your journey and have your car checked immediately.

Why Does the Check Engine Light Come On

There are several reasons the Check Engine warning light on your dash will turn on. Some of the most common reasons are the following:

1. Bad Spark Plugs

The spark plugs provide the sparks that will ignite the air/fuel mixture inside the combustion chambers of your vehicle. If they can’t provide the sparks to burn the mixture, the engine won’t be able to rotate.

Without the engine rotating, no power will be produced, and your car won’t run. Even if just one spark plug does not provide the required sparks in its assigned chamber, your engine will misfire. It will adversely affect your car’s fuel efficiency and make its emissions a pollutant to the environment.

2. Bad Mass Air Flow Sensor

The MAF sensor determines the amount of air inside the combustion chambers. So, it measures the amount of air coming inside the engine. This sensor is susceptible to dirt and oil buildup, which is always possible in all automotive engines.

Cleaning this sensor may do the trick. You need to replace this MAF sensor if it can’t fix the issue. Once you do this, the Check Engine warning light will fade away.

3. Loose Gas Cap

If you forget to close your gas cap tightly after a gas up, the fuel vapors inside the tank will be able to escape outside. This small detail you forget can trigger the turning on of the Check Engine light. The obvious fix is to tighten the gas cap each time you put fuel in your tank.

If you’ve done this and you don’t see the light turning on again, that’s your original problem.

4. Bad Cat Converter

Your car has a catalytic converter that changes the carbon monoxide produced by your car emissions to carbon dioxide, thereby protecting the environment. If you keep failing your emission test, this may be the root cause of your problem.

It will also reduce your fuel economy. By replacing a faulty cat converter, you may be able to fix this problem. However, the most common cause of this issue is a blown head gasket.

This condition will force burnt coolant vapor into your car’s exhaust. So, before you replace the cat converter, you better have the problem diagnosed by a competent mechanic first.

How to Find What’s Wrong with a Car’s Check Engine Light?

It will be detrimental if you react to this situation with panic. Sure, it is worrisome to suddenly have a warning light on your dash, especially the Check Engine light. You can assess your situation first while remaining calm and collected.

Ask yourself: how did this warning light come on? Then recall what you did before it came on. There are many possible things that you have done to trigger this light. If you can’t be sure, here are some suggestions:

  • Your car was jolted, or it vibrated because of something. If your vehicle makes strange movements that you didn’t cause, or if your spark plugs fail, you need to call a mechanic to fix the problem.
  • You recently gassed up. Perhaps you forgot to tightly seal the gas cap after going for a gas-up. Check your gas cap to see if it’s not tightly sealed to the gas tank.
  • Is it a blinking or a steady light? The Check Engine lights in some vehicles are two types. One blinks, and the other is steady. What’s yours? If the light flashes, it might be a severe issue, but if it is just steady and not moving, it may not be too serious a problem.
  • Did you hear strange noises before the light turned on? If this is the case, you should immediately stop driving your car and park it in a safe place. There could be something serious that happened to your vehicle. Call for a tow truck to get your vehicle to the nearest car repair shop.

Is It Safe to Drive A Car With a Check Engine Light On?

Can you drive your car safely with its Check Engine light on? It depends on the real cause of why the warning light was triggered. If it was triggered because of a loose gas cap, just tighten the lid, and you can go on your way.

However, if a minor problem does not cause it, you need to have your car checked before driving it as you are doing before.

Don’t ignore this warning light. It is there to alert you of something bad happening to your engine. It’s better to play it safe than to spend so much on repairing something that could have been avoided if you were just careful enough.

Frequently Asked Questions

what should you do if the check engine light comes on

If you still have some unanswered questions in your mind, perhaps the answers to one of these questions are listed down below:

Why Did the Check Engine Light on My Dash Come On?

The Check Engine light is a warning light that alerts you if something wrong is happening in your car engine. If this light comes on suddenly, don’t panic. Hopefully, you can reset the light by doing something simple like closing the gas cap tightly.

However, there are serious reasons why this light will come on. It may be that your cat converter or your MAF sensor is no longer working. Have a mechanic check your car as soon as possible to fix the actual cause.

Is It Okay for Me to Drive My Car Even with This Warning Light Turned On?

It depends on why the light came on in the first place. If it’s a minor reason, you can still drive it. But if a more severe problem triggers it, you must stop driving and bring your car to the nearest car repair shop for a checkup.

What Can Cause the Check Engine Light to Come On?

There are several reasons why this warning light can suddenly appear on your dash. Some of the most common reasons are:

  • Bad spark plugs
  • Failed MAF sensor
  • Loose gas cap
  • Failed cat converter

In Closing: When the Check Engine Light Comes On, What Do You Do?

Whether it is a blinking or a solid light, if this happens, the best you can do is drive your car to the nearest car repair shop. There could be any number of things that caused this light to turn on. You will need a car mechanic to pinpoint and fix the problem.

You should immediately stop your car if its Check Engine light is constantly blinking. Bring it to the nearest car shop as soon as possible so they can examine it. If you need to call for a tow truck, then use your best judgment.