What Does It Mean When My Check Engine Light Flashing?

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check engine light flashing

It’s the worst-case scenario for any vehicle owner. You’re running your car down the road; things seem to be normal until you notice your check engine light flashing out of nowhere. OMG! What is this?! Why is it flashing?

Numerous factors might cause your check engine light to flash. Even if your vehicle seems to be operating normally, you should schedule an appointment with a mechanic as soon as you can. Ignoring a minor issue may result in more extensive and costly problems.

The unexpected and abrupt coming of the check engine light may induce a particular sensation of panic. Our worries aside, the car is attempting to alert us that something isn’t well, and we’d do good enough to pay close attention when the light glows up.

But what if you notice your check engine light flashing? Is that a minor issue, or is it worse? Continue reading and learn what this means and how to deal with it.

Check Engine Light: What It Is and Its Function?

Your car’s check engine light is one of the series of tiny indicators located in the dashboard. It activates when the car’s Electronic Control Unit detects a failure code from one or more of its several sensors.

Your vehicle is equipped with a network of sensors that continuously monitors various parts and operations and communicates with the car’s internal system or computer. The system evaluates the information from the sensors and makes any required adjustments to the system through actuators.

When it detects an error that it cannot rectify, it notifies you by lighting an indicator or warning light on the dashboard. The light may activate for a particular reason, such as a low coolant level or low tire pressure.

Still, various engine faults will manifest under the “check engine” warning light. When this light occurs, the computer registers a fault code in its storage, which can be read using an Onboard Diagnostics (OBD II) scanner.

It’s worth noting that just possessing a code does not imply that you’ve uncovered the fundamental problem. While a code may put you on the right track, more diagnostic and service work will undoubtedly be required.

Causes of Flashing Check Engine Light

Generally, check engine lights will not flash until there is a serious issue with the car’s fuel or exhaust system. This warning light usually glows with a steady light. A more likely reason for flashing check engine light is when the car’s catalytic converter is harmed due to the transpiring issue.

The following list highlights some of the most prevalent causes of this check engine light flashing.

Engine Misfire

As fuel is injected inside the combustion chamber, the piston pushes to compress the air/fuel combination, but no combustion happens; this is referred to as a misfire. This may occur for various causes, including a bad spark plug, malfunctioning fuel injectors or fuel injector mechanism, or even piston failure.

This is the most common cause of the check engine light flashing since unburnt fuel may seep into the exhaust system and the catalytic converter. Unburnt fuel entering the catalytic converter may ignite and destroy the converter’s internal component, obstructing exhaust flow and preventing hazardous fumes from converting.

Ignition System Issues

You’ll notice your check engine light blinking if the ignition system’s components such as seals, spark plugs, or ignition coils are malfunctioning or leaking. It is one of the most typical causes of engine misfires.

Oil may seep into the engine’s combustion chamber, obstructing the necessary charge from the spark plugs for detonation and resulting in a misfiring engine. Unburnt oil, if it gets thru the exhaust manifold and makes its way into your precious catalytic converter, may likewise have a similar impact as unburnt fuel.

Replacing O-ring sealings or spark plugs are standard preventative maintenance treatments that you can DIY to see whether the problem is resolved.

Fuel Leak

Another possible cause is leaking fuel. Fuel pumps could be pumping fuel through the engine, but the engine could never get it. Additionally, fuel might be seeping around somewhere or within the engine.

Bad Oxygen (O2) Sensor

A defective oxygen sensor might prevent the engine from receiving the required fuel. Even a functioning oxygen sensor may supply what it considers to be the correct quantity of gas to the car’s engine due to inaccurate readings from an airflow sensor.

Engine Components Defect or Engine Damage

Even though engine damage does not harm the catalytic converter, it may cause your car to surprise you with a flashing check engine light. Although timing chain, valves, and piston failure are uncommon causes of this issue, they are some of the most catastrophic reasons for this to occur.

Most often, other indicators of engine damage will manifest themselves before or during the lighting of a warning light, such as loud engine noise, a shaking car, or even shutdown of the engine. Any harm to an engine component might result in the engine failing completely, requiring a rebuild or replacement.

EGR Valve and EVAP System Malfunction

Evaporative Emissions Control (EVAP) is a system that balances fuel fumes released by a car’s fuel tank. At the same time, Exhaust Gas Recirculation (EGR) is meant to put back into the circulation of the exhaust fumes to a car’s intake to decrease hazardous emissions.

When one of these several systems malfunctions, a car’s emissions system operation is affected and might cause flashing check engine light.

A frequent and surprisingly straightforward technique to remedy this issue is to remove the fuel cap and put it back after. It doesn’t usually fix the problem, but you’ll be amazed that it can sometimes.

Faulty Fuel System

When any of the fuel system components malfunctions, a sensor transmits incorrect info to the Electronic Control Unit, there is a chance that you will see a check engine light flash.

Fuel system malfunctions are the most common cause of engine misfires. The engine receives various quantities of fuel based on factors like the air intake sensors and throttle position sensor. If any of these sensors fail, enough fuel volume required to flow to the engine may not be achieved.

Electrical Issues

Electrical and circuit difficulties may create a slew of issues for a car, and a power shortage might do the same. When a sensor ceases to receive data, it cannot relay data to the ECU, resulting in a fault code.

If the ECU cannot get the data required, it may do anything from flashing engine light to completely shut down the car, based on what sensor is not receiving signals.

This might be caused by disconnected wiring or a lack of alternator or battery power, although this is very improbable.

Gasket Failure or Vacuum Leak

When air, engine oil, or fuel misses a sensor and enters areas where it should not, your car’s engine and some other parts may fail. A leaking vacuum may seem to let more significant air into the engine, leading the car’s ECU to indemnify and deliver extra fuel even if it’s not required.

This, too, may result in a misfire owing to an overabundance of fuel in the engine’s combustion chamber. Similarly, a gasket malfunction might result in oil and coolant leakage into the engine and subsequently into the exhaust, perhaps leading to a catastrophic catalytic converter failure.

Check Engine Lights: Steady vs. Intermittent vs. Flashing

Check engine lights have three different ways of warning, and each form of lighting has a different meaning. Let’s see below what each lighting means.


Sometimes a steady check engine light can glow for no apparent reason, such as a loose fuel cap, but most frequently, it’s because of something more severe, and you can’t be sure what it is until you have a scan. Make an appointment for a scan as early as possible to determine if you have a significant issue or not.


This is whenever your check engine light turns on, then dims, and then brightens again after a while. This is often indicative of an engine sensor malfunction. Additionally, you may suffer occasional engine misfires, indicating a faulty ignition coils or the ignition system. When this occurs, you can still run your vehicle safely. However, as always, we suggest identifying and resolving the issue as quickly as possible.


A flashing check engine light is intended to call your awareness and most often indicates an urgent situation that cannot wait. Indeed, when your check engine light is blinking, you may wish to alter your plans and quickly drive to a repair. When the light is flashing, your car makes no guarantees that it will get you to your destination, and you may even want to have your vehicle towed.


There is no surer method to avoid engine misfires and a blinking check engine light than to adhere to your car’s recommended maintenance schedule. Routine inspections can assist you in identifying which components need replacement to maintain your car’s best performance.

Additionally, do not ignore a flashing or blinking check engine light. Have your car inspected immediately by a skilled mechanic to avoid minor problems becoming severe.


Can I drive my car with the check engine light blinking?

As a general rule, if you notice a flashing engine light, you cannot keep running the vehicle even if it can still run. Frequently, it is indicative of an engine misfire. If you continue driving, you risk causing irrevocable harm to the vehicle, most notably the catalytic converter, which is pretty expensive.

What can cause a check engine light to flash?

Various issues can surprise you with a blinking check engine light. These causes are unpredictable; they might be a minor issue or a massive headache. These issues could be a loose gas cap, bad catalytic converter, faulty oxygen or mass air flow sensor, malfunctioning spark plug, faulty fuel injectors or an engine misfire. Minor or not, it is recommended that you fix these issues right away to avoid more damages.

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