Why Is My Check Engine Light Flashing?

February 14th, 2023
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You’re driving your everyday route to work. Suddenly, the light flashes on your dashboard. It’s your check engine light. Why now? What’s the reason your check engine light has just come on?

Let’s explore the topic in detail and analyze the four most common reasons for a flashing check engine light.

Why You Should Not Ignore a Flashing Check Engine Light 

A flashing check engine light indicates a serious operating problem within your vehicle. The system is built based on a progressive alert system. If the vehicle’s check engine light goes from simply being on to flashing, there’s likely an engine issue that poses a serious danger to you and your passengers. You should immediately take the car to a local auto shop to run diagnostics on the flashing light and to ensure the vehicle is safe to drive.

The Most Common Causes for a Flashing Check Engine Light

Below are a few of the leading reasons for a flashing check engine light:

Ignition System Problems

That flashing check engine light could be associated with ignition system issues. Your ignition components combine to create the spark that fires the engine to ignite the air/fuel mixture. Whether it’s a problem with the ignition coil or a faulty starter, the ignition system is a likely culprit for a flashing check engine light.

Fuel Injection Malfunction

Your car’s fuel injectors deliver fuel to the engine cylinders. When they become clogged with debris, your engine doesn’t receive an adequate fuel supply for efficient combustion. Fuel injector malfunction can result in an engine misfire, which may lead your vehicle to break down if you’re driving at high speeds. 

Worn Piston Rings

Your engine’s piston rings compress the air and fuel mixture to drive combustion. The pistons within your vehicle have two piston rings, which help to seal the cylinders and prevent compression loss. Worn-out rings cannot seal engine cylinders and can create the conditions for a misfiring engine, which causes smoke to emerge from your tailpipe.

Overheating/Failed Fuel Pump

Your flashing check engine light could also be related to a failed or overheated fuel pump. If you often drive the vehicle when it’s low on fuel, you place additional demand on the fuel pump and its connected components, causing premature wear and forming the conditions for fuel pump failure.

Flashing Check Engine Light Questions

Beyond knowing why your car’s check engine light might suddenly start flashing, you likely have specific questions about your vehicle’s performance and how it relates to your engine light.

Why Is My Check Engine Light Flashing When I Accelerate?

If your check engine light specifically only flashes when you accelerate and is otherwise static or off, it could be a problem with the engine overheating, an oxygen sensor, low oil pressure, or, if you’re lucky, a loose gas cap.

Why Does My Check Engine Light Flash And Then Go Off?

In some cases, when you have a faulty oxygen sensor, for example, your check engine light will flash and either stay on or go off. 

You’ll likely experience intermittent check engine light indicators as the oxygen and fuel levels change. It’s important to note that even though the check engine light has either stopped flashing or gone off, the problem is likely still present and will recur as you drive.

Do Bad Spark Plugs Cause Check Engine Light to Flash?

In some situations, the fault for the flashing check engine light could be bad spark plugs. Spark plugs can cause your engine to misfire, leading to hazardous engine conditions. It could be the spark plug electrodes are degrading or rust on the spark plug. 

How Long Can I Drive with a Flashing Check Engine Light?

There’s no specific time limit for a flashing check engine light. If you’re driving when the engine light starts flashing, go straight to a nearby mechanic. However, if the engine light starts flashing when you start the vehicle, it’s safer to tow the car to a repair facility.

Does a Faulty Gas Cap Cause a Flashing Check Engine Light?

If you’re lucky, it could be that your gap cap is not tight enough. A loose gas cap can allow vapors to escape the fuel tank and impact fuel efficiency. If you notice the engine light immediately when starting the vehicle, this is one of the first and simplest areas to check.

Call Local Langley Mechanics for Check Engine Diagnostics

Engine lights are a sign of a significant vehicle engine issue, and flashing engine lights require immediate attention from a local engine service expert. 

Call our Langley mechanics today if you have a flashing check engine light. Or head to our Langley auto repair shop at 5672 Production Way, and we’ll run an engine diagnostic for you. 

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