Flashing Check Engine Light Then Stops: Causes, Solutions & More

Check Engine Light Flashing

Typically, a continuously brightened check engine light is normal and indicates you need to get maintenance on your vehicle. However, a blinking check engine light is cause for concern. Furthermore, if your car has a flashing check engine light then stops running, this usually indicates a serious issue. You probably should get your car to a repair shop as soon as possible. 

Put simply, if you see a flashing check engine light, it could mean trouble. In this article, we’ll examine what causes a flashing check engine light then stops situation, what a flashing check engine light might be caused by, and ways you can prevent it. Please read this information to ensure that you’re safe when driving your vehicle and to avoid long-term damage to your car.

Put simply, if you see a flashing check engine light, it could mean trouble. In this article, we’ll examine what causes a flashing check engine light then stops situation, what a flashing check engine light might be caused by, and ways you can prevent it. Please read this information to ensure that you’re safe when driving your vehicle and to avoid long-term damage to your car.

Different Engine Light Codes and What They Mean

Flashing Check Engine Light

The diagnostic check engine light codes are usually divided into four groups. They’re usually at the root of a situation when your car experiences a flashing check engine line then stops running. However, they may also be paired with a flashing check engine light that doesn’t cause your vehicle to stop. These four different diagnostic groups include:

  • C: These alerts indicate that something is wrong with your chassis. For example, trays underneath your car might be loose and dragging on the ground, which can be a very serious issue.

  • U: When you see this alert, your network communications are down or struggling. This issue might mean that your car’s Bluetooth or satellite radio systems don’t work properly.

  • P: Powertrain problems can include problems with your engine, the transmission, and other important sections of your car. Often, P errors are those that will cause your car to fail most quickly.

  • B: A B code typically indicates bodily problems with your vehicle, including problems with various parts attached directly to it. It’s important to track these issues quickly before they worsen.

Typically, there are also various, more in-depth codes that indicate more precisely what is wrong with your vehicle. For a broader understanding of the meanings of these codes, we’ve listed the most relevant codes for most vehicles and highlighted what they mean when you see them:

Engine Misfires (Codes P0300-P0305)

Apart from code P0300, all the other codes in this category let you know that there is a problem with your cylinders. The P0300 indicates that there are multiple misfires in multiple cylinders. The other codes indicated engine misfires in cylinders 1 to 5, respectively.

Piston failure can cause your vehicle to run very poorly and trigger misfires that may affect your efficiency. Therefore, your mechanic might need to change any cylinder that has a misfire. They’ll quickly assess the situation and provide help with this unique problem.

Sensing Oxygen Levels (Codes P0171 – P0175)

This set of codes quickly diagnoses whether the oxygen levels in the system are functioning correctly. Some of the codes indicate whether the engine is receiving too much or too little air, while other codes focus on the air sensor. Without proper oxygen flow, your car’s engine will struggle.

If the oxygen sensor is underperforming, it will need to be changed out by a certified mechanic. You typically don’t want to try this process yourself because it’s far too easy to damage your system instead. Working with a mechanic can minimize the danger of this issue.

Catalytic Converter (Codes P0420, P0430)

These codes generally report that the catalytic converter is spoiled and needs to be changed. If the catalytic converter is not functioning at maximum capacity, then the check engine light flashing should alert you that there is a problem using one of these two codes.

Note that the check engine light also serves as a warning when the O2 sensors are malfunctioning and affecting the catalytic converter. Pay attention to your car’s exhaust if you see this light because it might come out darker (which indicates a far more serious issue at play).

Evaporative System (Codes P0411, P0440, P0442, P0446, P0455)

These codes indicate that your car’s secondary injection system has an incorrect flow and that there might be a complication with the evaporative emission control system. Furthermore, one of these codes also indicates that there is a bad vent control valve or that you have a loose gas cap that needs to be replaced. The latter step is pretty easy and is something you can do yourself.

However, you shouldn’t try to handle things like replacing the vent control valve because it’s far too easy to make a mistake and impact your car’s operation. Without this valve, your system might run less efficiently, so make sure that you contact a mechanic to get help right away.

Exhaust Gas System (Codes P0401)

This trouble code shows that there is a complication with the exhaust gas recirculation system. It indicates that the system is not functioning sufficiently. Different components come together to ensure that there is sufficient recirculation of exhaust gas so that there is no release of very toxic gasses.

Failure to repair your exhaust system could also be dangerous to your health. Those toxic gasses could easily get into your car and cause a serious poisoning risk. Even a small amount can be bad for your health, so make sure you take this situation seriously to stay safe.

Types Of Engine Light Illuminations

Different Engine Light Codes

As we have previously stated, when you see a flashing check engine light that then stops your car, there’s something wrong with your vehicle. A flashing check engine light acts as a warning system that there is a problem with the vehicle, including many of its systems.

In some cases, it can be a minor problem, but it is a major issue in others. Therefore, it’s important to find ways to determine whether you need to pull over immediately and call a tow service or keep driving and take your car in for diagnostics in a few days to get repairs.

Thankfully, there are at least three ways to know what your check engine light means. If you pay attention to how the check engine light illuminates at different times (especially if your car is still running smoothly or can get enough power), you can keep your vehicle safe.

i) Continuous Engine Light Flashing

A continuously flashing engine light is usually a bad sign. If your check engine light is always blinking or flashing continuously, you should pull over immediately and call a local tow service. If the check engine light blinks continuously, it is indicative of a severe problem with the engine.

A rapidly blinking light is one of the things that most drivers dread because it could mean a costly repair and inconvenience. Problems you might experience include misfiring issues, low fuel pressure, faulty engine sensors, and even a potential complete engine failure.

ii) Irregularly Flashing Light

If the check engine light flashes for a while then stops, it is indicative of a minor issue. Such failures are usually soft failures. A soft failure is an issue such as a loose wire that disconnects and connects. The irregular flashing of the check engine light is caused by a faulty wire rapidly disconnecting.

Thankfully, this problem usually indicates a relatively minor issue that you can quickly get fixed. For example, your mechanic can simply tighten a wire properly to ensure that your car isn’t seriously damaged. It might even include carefully replacing some minor parts of your vehicle.

iii) Continuous Illumination

When the check engine light is continuously on, it means there is a severe problem that needs immediate attention. However, you can usually continue to drive your car for some time with this light on, including getting to and from work, picking up your kids, and other steps.

However, it is always the safest option to go to a professional mechanic for a diagnosis. The problem is usually cheap to fix, even if it’s a major issue. As a result, it’s a good idea to drive your car directly to a mechanic and get emergency repairs just to make sure a major issue doesn’t worsen.

Common Causes of a Flashing Check Engine Light

There are multiple causes for a flashing check engine light that then stops. Typically, it’s indicative of problems wrong with your car, such as not getting enough power when you need it. If your flashing check engine light is coupled with other characteristics, then you might be in trouble. 

As a result, it’s important to know more about what causes your flashing check engine light and how this might impact your vehicle. Just as importantly, it can help you know exactly what repairs you need without fail. Here are some reasons why you have a flashing engine light.

1) Faulty Oxygen Sensor

If you have a faulty oxygen sensor, the fuel delivery and fuel combustion will be affected. The oxygen sensor monitors how much oxygen and unburned fuel is exhausted in your engine. When the oxygen sensors have a problem, the airflow is disrupted. 

Furthermore, the oxygen sensor readings inform your car's fuel-to-air ratio to maximize your car's performance. Additionally, there are one or two things you can check to confirm whether your oxygen sensor is operating at optimum level without major issues.

For example, your car could be stalling or have increased exhaust after your flashing check engine light then stops unexpectedly. Sadly, a faulty oxygen sensor will slowly affect your catalytic converter, which is terrible for your car and could potentially impact its overall operation.

2) Bad Airflow Sensor

As part of your vehicle's electronic fuel injection system, the airflow sensor is responsible for calculating the volume of air injected into the engine. The airflow sensor is a major component of your fuel injection system and is, therefore, vital for your vehicle’s efficiency.

Additionally, the car computer uses airflow readings to determine the differences in the automatic transmission. If the airflow sensor doesn't work correctly, the differences in the automatic transmission will be more pronounced, and your car could be at a higher risk of failure.

Either way, if your airflow sensor is wrong, it will cause poor acceleration, no start, and the flashing light of the check engine. It can also cause an engine misfire.

3) Loose Fuel Cap

A loose fuel cap is not usually a major cause for concern. After all, it’s something that you can probably fix yourself. Nevertheless, it won't stop your car computer from throwing an error code. Note that a loose cap might be due to various other issues and not just a one-time thing.

Furthermore, a loose fuel cap can cause problems in your car's emission system. So, while it is possible to drive around with a loose gas cap, if you notice a flashing check engine light, you should take your car in for immediate repair. It allows impurities to enter your car's fuel system. The signs of a loose fuel cap include:

  • Problems tightening the cap caused by stripping out the system

  • Discoloration around the entry point of the gas tank caused by debris buildup

  • A gasoline smell that is ever-present when you drive or even while parked

4) Worn-Out Spark Plugs

Faulty spark plugs are one of the main causes of engine misfires. A spark plug creates a spark that ignites the air and fuel mixture in your engine to give it power. It's a small device tasked with many jobs. The voltage that the spark plug produces can range between 20,000v to 100,000v. 

Symptoms of faulty spark plugs or an ignition system defect include engine misfires, slow acceleration, difficulty getting your car to start, and a flashing check engine light. Note that old spark plugs tend to be faulty, which could seriously impact how well your vehicle runs and operates.

5) Bad Catalytic Converter

A catalytic converter converts toxic gasses from the exhaust gas into less toxic pollutants. While it is possible to drive around without this converter, it is also not recommended. A faulty converter will not affect your engine in any significant way but can cause heavy pollutants in the air.

Some of the symptoms of a faulty converter include a foul smell from the exhaust pipe, overheating under the car, reduced acceleration, and a sluggish performance of the engine. However, the most telling symptom includes dark exhaust smoke. Pay attention to these issues to diagnose a problem.

6) Failed Fuel Injector

A fuel injector sprays fuel into the engine's combustion cylinders after it mixes with the air. Driving your vehicle with a faulty fuel injector will cause more than a few serious problems and extreme damage. Most injectors should be replaced every 50,000 to 100,000 miles to avoid issues.

Symptoms of a faulty injector include engine vibration that causes surges in movement. Common causes of falling fuel injectors include debris, dirt, rust, and other foreign materials making their way into the car system. Pay attention to the sound of your car, as it might be louder than normal.

7) Failed Engine Computer

An engine computer is tasked with the job of making immediate adjustments. In most vehicles, the function of the engine computer is to manage the engine timing and the fuel-to-air ratio. It uses information from multiple sensors to perform all its primary and assisted functions.

When your engine computer fails, you’ll get a flashing engine light that then stops at various times. Symptoms to look out for include your engine shutting down without reason, a sudden drop in fuel economy, a sudden loss of acceleration and stuttering, or a misfire in your engine. 

8) Faulty Ignition Coils

A car’s ignition coils work along with your spark plugs to help keep your fuel igniting quickly and efficiently. If they end up failing you, there’s a real problem here. Your flashing check engine light might indicate this problem, particularly if your car fails to start at all.

You might also notice that your car doesn’t run smoothly or that it runs in jerks and starts. That’s because the ignition coils might fail to run smoothly and cause the car to stall. It’s critical to talk with your mechanic to ensure that you take care of this problem quickly.

What to Do When Your Check Engine Light is Flashing

If you see a flashing check engine light that then stops, make sure that you know what to do about this issue. There are several steps that you need to take that can immediately assess your situation and keep your vehicle safe.

Don’t Ignore the Light 

Immediately diagnose what is happening with your vehicle by taking your car to a mechanic. Ignoring a flashing light is never a good idea and typically causes severe damage to your vehicle’s engine. Assess the situation and decide if you need to drive right to a mechanic’s shop or can wait.

Pull Over Immediately 

Try to pull over safely and park your car somewhere where you can check various items quickly. Obviously, you’re probably not a mechanic, but you can check the gas gap to see if it’s loosened and tighten it. Look for other potential problems, such as broken belts on your engine.

Drive to Your Mechanic 

If your vehicle is still running, it’s important to turn on your hazard lights and slowly drive to your nearest mechanic. From here, they can provide you with a diagnostic test to figure out what’s wrong. Don’t drive your car if the engine is obviously struggling or if it is overheating or even smoking.

Talk to Your Insurance Company 

There might be a chance that your insurance company will pay for your repairs. It’s critical to reach out to your provider to report this problem. If you need a tow, you can contact them to get it covered but note that your policy may increase as a result. That said, it’s still better to use it than not.

Make Personal Plans

It’s critical to make various plans while your car is getting repaired. For example, you need to find transportation to and from work, as well as budget your repair expenses. Doing so can ensure that you don’t experience any personal or financial problems related to your car’s breakdown.

Preventing a Flashing Check Engine Light 

The old cliche says that a pound of prevention is worth an ounce of treatment. As a result, it’s important to know how to prevent a flashing check engine light that then stops. The following steps can ensure that your flashing check engine light is properly managed and effectively repaired:

  • Regular maintenance that minimizes potential damage issues

  • Proper fuel usage, including filling your tank when necessary

  • Addressing issues promptly instead of letting them worsen with time

  • Running your HVAC system less heavily to avoid wearing it out

  • Doing a complete electrical overhaul if your system is malfunctioning