What To Do If The Check Engine Light Is Flashing Then Stops?

Unfortunately, we all know how expensive engine repairs can be. So when you suddenly see a check engine light pop up on the dashboard, flash its evil eye at you a few times, and then cryptically disappear, it can make you feel uneasy.

There are so many different light signals on the dashboard, and it's okay not to remember every one of them. But I believe it's definitely worth remembering some of the most important ones, like the check engine light.

The check engine signal can start angrily flashing at you for various reasons. It can be a computer malfunction, or it can signal that something inside the engine system has gone bad and requires your immediate attention.

It's a shame that dashboard signals can only inform you that something is wrong without providing any specifics. So, we decided to delve deeper into this issue and explain the most common reasons why you might experience a flashing check engine signal and what you should do about it.

How Serious Is A Check Engine Light?

Needless to say, combustion engines are dangerous. They should never be taken lightly. So if you see a blinking check engine light, pull to the side and turn the engine off. It doesn't mean that your engine will blow up immediately if there's something wrong with it. Think of it as minimizing the risks of major repairs and large bills.

The most common reasons your check engine light starts blinking are a clogged air filter or a low oil level. If you're fortunate enough to have a replacement, carefully replace the affected part and check again. If you start your engine and no check engine light illuminates, congrats, you've resolved the issue.

It doesn't always have to be a groundbreaking, irreparable problem. This light generally indicates that there's an issue preventing the engine from working properly. And the actual problem can be quite minor.

However, it's a bad idea to ignore such a signal. Ignoring it can have serious consequences for your vehicle. Addressing problems promptly when you first notice them is the most economical approach.

What Does It Cost to Fix Your Check-Engine Light?

In the most optimistic scenario, the repair will cost you next to nothing. However, the most costly repair, such as replacing a catalytic converter, can exceed $1,000.

The good news is that this cause for a check engine light is relatively rare and doesn't occur without preceding warning signs. You can prevent this issue by regularly checking your vehicle and being attentive to certain signs.

You might suspect something's wrong with your catalytic converter even before the check engine light illuminates. Don't overlook when your car seems sluggish, heats up quickly, or emits dark smoke from the exhaust. These are indications that you should get it thoroughly inspected.

Costs To Fix The Check Engine Light-Related Issues

Whatever the reason, once you see a bright orange or yellow check engine sign, it's a valid reason to be concerned and look into it. It can get pricey to fix the issues, but it doesn't come near to the repair costs if you choose to ignore it. It always starts with something small and then escalates into real problems.

Just remember that every minute you're driving with a flashing check engine light, your engine suffers from some kind of damage. It accumulates into much bigger issues over time. And we all know that replacing is hardly an option because it's too expensive.

What Can Trigger A Flashing Check Engine Light?

When you see a flashing check engine light on your dashboard it means that your engine is most likely in danger. It only lights up and starts blinking when the system decides that there is a risk of engine overheating, misfiring and potentially getting more damage than it can handle.

There's, of course, a possibility that it's a false alarm due to a malfunction in the computer or sensors. But the best course of action is to stop the car in a safe spot and try to determine the cause.

Here's a list of potential issues that might cause a check engine light to flash and then stop. Hopefully, this list will assist you in troubleshooting.

Faulty Oxygen Sensor

A perfect balance of oxygen and fuel during combustion is crucial for your engine to work smoothly. Your O2 sensors our responsible for spotting any anomalies in the air-to-fuel ratio. If something happens to the oxygen sensor, there is no telling how much air comes into the system.

The oxygen sensors can malfunction, deteriorate over time, have a defect or simply get too dirty to function. This might not seem like a big issue at first, but if the faulty oxygen sensor issue is left unresolved, it will result in catalytic converter problems later on. And that's the rest expensive parts you can get damaged in the process, so no issues too small.

To pinpoint the culprit, pay attention to excessive exhaust or stalling. System codes can also help you identify the reason behind the flashing message.

Airflow Sensor Fault

Your engine needs a goldilocks situation with just the right amount of air supplied each time for combustion. Pump too much or too little, and the performance will drop significantly. The airflow sensors are responsible for maintaining that precise balance.

The computer in your car relies heavily on this sensor's readings to determine how much air to supply to the engine. When something goes wrong, the information from the sensor becomes distorted, causing disruptions in the engine's operation.

You will know that there is something wrong with your airflow sensor if there are problems with acceleration and starting in addition to the flashing check engine light. This issue often results in engine misfires into other problems. It should be resolved as soon as possible to avoid any lasting damage to your engine.

Loose Fuel Cap

This probably happened to almost every car owner at least once in their life. If you didn't screw the gas cap well enough, the ever-watchful sensors will know and try to warn you that something is off with the fuel and engine system. Consider yourself very lucky if this is the reason why you have a flashing check engine signal on the dashboard. Because it's free to fix and takes no time at all.

Take a moment to check if your gas cap is secured in place and you cannot smell gasoline fumes. Another telltale sign that your gas cap is not tight is the smell of fuel inside your car.

You should not ignore this issue at all because it can disrupt the emissions system's work and pollute the fuel system

Worn-Out Spark Plugs

Spark plug problems aren't that uncommon. With an average lifespan of two to three years before you need to replace them, it's not a surprise that a worn-out spark plug can cause the check engine light to blink at you.

They cannot be ignored because the air-fuel mixture needs a spark to ignite and set the engine into motion. If they cannot provide that spark, you will definitely get some engine problems.

You will know that the spark plugs are at fault after you experience engine miss fires and problems with starting your car. Replacing faulty spark plugs at a shop can cost anywhere from $100 two $500 depending on many factors like the engine your car is using, the plug type, labor cost, etc. The spark plug itself usually costs $5-$20, depending on the type of spark plugs you need.

It's totally worth it to address these issues promptly, as doing so can help you avoid more expensive repairs down the line.

Faulty Catalytic Converter

When your catalytic converter begins to fail, your car's performance will decline, and it may overheat. The most noticeable symptom of a bad catalytic converter is dark smoke from the exhaust.

Catalytic converters make your car less harmful to the environment by breaking down toxic gases into less dangerous ones.

Fuel Injector

We have already talked about the airflow sensor. Now let's talk about the second integral part of combustion, fuel injection. When the fuel injectors get busted, your engine doesn't receive enough fuel to do its job. They can get damaged, blocked or simply wear out.

Among the most common symptoms of a failing fuel injector you can encounter vibration and surges while your car is moving. An uncharacteristically loud engine sound can also hint at this issue.

ECU Problems

And last but not least, the computer itself. This entire process is controlled by a computer or ECU. It's also not immune to glitches and malfunctions. When it's out of order, it cannot effectively control and adjust the air-to-fuel ratio.

Before you see a check engine light due to this exact problem, you will likely experience a significant drop in fuel efficiency. And other warning signs are sudden loss of acceleration, misfires or unexpected engine shutdown.

This is probably one of the most dangerous issues. Unfortunately, it's hard to pinpoint if you're not an experienced car mechanic. You will probably need a special scanner to catch this problem.

Deciphering The Check Engine Light Codes

An OBD-II scanner isn't a very common tool in everyone's car or garage, but it's invaluable for detecting and identifying problems that triggered the check engine light. It can read error codes from the onboard diagnostic system, which you can interpret to determine the exact malfunction.

Each specific problem has a unique code to identify it. Without them, you would be in struggling to find the area where the problem occurred.

Codes P0300-P0305: Engine Misfires

• P0300: Random/Multiple Cylinder Misfire Detected.
• P0301: Cylinder 1 Misfire Detected.
• P0302: Cylinder 2 Misfire Detected.
• P0303: Cylinder 3 Misfire Detected.
• P0304: Cylinder 4 Misfire Detected.
• P0305: Cylinder 5 Misfire Detected.

If you encounter these codes, it signifies that one or several cylinders might be the issue. This information might not be overly detailed, as any of these problems could be due to bad spark plugs, compression issues, fuel delivery problems, or other causes.

Codes P0171 – P0175: Sensing Oxygen Levels

• P0171: System Too Lean (Bank 1).
• P0172: System Too Rich (Bank 1).
• P0173: Fuel Trim Malfunction (Bank 2).
• P0174: System Too Lean (Bank 2).
• P0175: System Too Rich (Bank 2).

All these codes describe the mixture of fuel and air, so when you see the word "rich" it means that there is too much fuel in the air. And vice versa, the word "lean" means there's too little fuel in the mix.

Codes P0420, P0430: Catalytic Converter

• P0420: Catalyst System Efficiency Below Threshold (Bank 1).
• P0430: Catalyst System Efficiency Below Threshold (Bank 2).

These codes mean that there is something going on that's disrupting the normal catalytic converter's work.

Codes P0411, P0440, P0442, P0446, P0455: Evaporative System

• P0411: Secondary Air Injection System Incorrect Flow Detected.
• P0440: Evaporative Emission Control System Malfunction.
• P0442: Evaporative Emission Control System Leak Detected (small leak).
• P0446: Evaporative Emission Control System Vent Control Circuit Malfunction.
• P0455: Evaporative Emission Control System Leak Detected (gross leak).

The evaporative system's purpose is to prevent fuel vapors from escaping into the external environment. It's a vague system, meaning that a problem could be as simple as a loose gas cap or something more complex involving valves or sensors.

Codes P0401: Exhaust Gas System

The EGR system recirculates some exhaust gases back into the intake manifold to decrease toxic gas emissions. This code indicates there's insufficient flow in the EGR system, which could be due to a blocked passage, a malfunctioning valve, or other related issues.