Blog Car Care Advice Check Engine Light Flashing: Meaning, What to Do + 6 Causes
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Check Engine Light Flashing: Meaning, What to Do + 6 Causes

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A Check Engine Light (CEL) is concerning enough itself, but things get more alarming when it starts flashing.

What is your car trying to say?
Can you drive with a flashing Check Engine Light?

Get answers to these questions and learn more about the Check Engine Light flashing.

This Article Contains:

Let’s get going!

What Does a Flashing Check Engine Light Mean?

A flashing Check Engine Light indicates serious trouble with your car and demands immediate attention. The most common reason behind the Check Engine Light flashing is an engine misfire.

The warning appears as an engine outline that blinks once every second. Some cars may use a steady red Check Engine Light instead of a flashing amber-colored symbol to signal a severe problem.

What should be your next step if you encounter a flashing CEL on your car?
Read on!

What Should You Do if the Check Engine Light Flashes?

Don’t drive with the Check Engine Light flashing. Pull over safely to the roadside and get your vehicle towed to an auto repair shop.

Driving while this warning light blinks can damage the catalytic converter due to overheating from engine misfires. An overheated catalytic converter is also a potential fire hazard.

Additionally, engine misfires cause power loss while driving and can put you in a dangerous situation on the road. If you have a misfire due to mechanical reasons rather than fuel delivery or ignition issues (e.g., worn piston rings, timing belt issues, etc.), you might be looking at high engine repair costs to fix the damage.

Now, let’s get to the causes that trigger this flashing light.

6 Common Reasons Behind a Flashing Check Engine Light

Multiple factors can cause an engine misfire, which triggers a blinking light on the dashboard – fuel delivery issues, a bad engine sensor, to name a few. We’ll touch on them here.

1. Faulty Spark Plug

Bad spark plugs usually cause an engine misfire and, thus, a flashing engine light. A malfunctioning spark plug won’t provide the required high-voltage spark for igniting the air-fuel mixture in an engine’s cylinder, causing a misfire.

2. Bad Ignition Coil

An ignition coil transforms low battery voltage into a high-voltage spike for the spark plug to function. The coil may be placed directly on top of each spark plug in the case of a modern vehicle’s engine or connected using spark plug wires in a distributor-type ignition system.

A bad ignition coil can result in an engine misfire for reasons similar to the spark plugs and trigger this flashing dashboard light.

3. Defective Fuel Injector

A bad fuel injector won’t provide enough fuel to the cylinder for combustion, leading to a lean condition and a misfire.

4. Engine Sensor Problems

The mass airflow sensor measures the air entering the engine. If this engine sensor is faulty, it can mess up the air-fuel ratio, resulting in a misfire.

5. Faulty Oxygen Sensor

The oxygen sensors in your car’s exhaust system help the ECM adjust the air-fuel ratio and keep a check on the efficiency of the catalytic converter. An engine misfire can occur due to an incorrect air-fuel ratio reading from an oxygen sensor.

6. Vacuum Leak

A damaged vacuum hose or intake manifold gasket allows unmetered air to enter the engine. This leads to a vacuum leak, resulting in an engine misfire and a flashing CEL.

Next, we’ll cover the noticeable symptoms you may experience along with a flashing engine light.

What Are the Key Symptoms Accompanying a Flashing Check Engine Light?

Here are the common signs that your engine is misfiring and causing the Check Engine Light to flash:

Have more questions about the Check Engine Light flashing on your dashboard?
Let’s address them. 

4 FAQs about a Flashing Check Engine Light

Here are answers to some common questions about this flashing light.

1. How Is a Steady Check Engine Light Different from a Flashing One?

A steady or solid Check Engine light generally means something is off with your vehicle’s engine or emissions control system (catalytic converter, O2 sensor, etc.), or you have a loose gas cap. It doesn’t always indicate a severe problem, unlike its flashing counterpart.

You can still drive your car with a solid Check Engine Light. However, you should reach out to an auto repair professional promptly to avoid serious issues later.

2. What Are the Common Flashing Check Engine Light Codes?

The following Diagnostic Trouble Codes (DTCs) can be present along with the Check Engine Light flashing on the dashboard:

3. Does Every Misfire Result in a Flashing Check Engine Light?

No, only “Type A” misfires result in a flashing Check Engine Light. They are identified by calculating the percentage of misfires during a 200-revolution interval of the crankshaft. Type A misfires can damage the catalytic converter. 

Type B misfires are detected by considering a 1000-revolution interval and don’t pose a direct threat to the catalytic converter. They can, however, raise the emission levels to 1.5 times higher than the Federal Test Procedure (FTP) standards and are indicated by a steady Check Engine Light.

4. Why Is the Check Engine Light Flashing after Changing the Spark Plugs?

The blinking check engine warning light may come on after replacing a faulty spark plug on your car because of:

Wrapping Up

A flashing Check Engine Light is mostly caused by engine misfiring and demands immediate attention. Ignoring the blinking Check Engine Light can damage the catalytic converter – an expensive exhaust system component, or lead to baffling engine repair bills. If there’s a Check Engine Light flashing on your dashboard, contact an auto repair shop promptly and get your car towed to it.

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