Worried about the check engine light flashing on your dash?
This warning is more than a minor hiccup — it often points to urgent issues that could harm your vehicle’s engine if left unchecked. To reduce further damage, you should avoid driving.
Wondering what to do next?
We’ll help you resolve the problem as soon as possible by explaining the reasons behind the flashing check engine light and what to do when yours illuminates.
This Article Contains:
- What Does a Flashing Check Engine Light Mean?
- What Causes a Flashing Check Engine Light?
- Can You Drive with a Flashing Check Engine Light?
- What to Do When the Check Engine Light Starts Flashing
- How to Reset a Flashing Check Engine Light: 3 Ways to Do It
- How Much Does Fixing a Flashing Check Engine Light Cost?
- How to Prevent Problems Associated with a Flashing Check Engine Light
What Does a Flashing Check Engine Light Mean?
The check engine light (CEL) is part of your vehicle’s warning system, alerting you to car issues that can cause an engine problem.
A flashing check engine light functions as an emergency warning, typically signaling a significant problem with your vehicle’s engine that requires immediate attention.
Is it different from a solid CEL?
Yes. A constantly illuminated check engine light also indicates a problem, but one that may not require immediate intervention. This can include the need for an oil change or filter replacement.
Moreover, when the CEL illuminates, it doesn’t typically display any specific information about the problem. So, diagnosing the issue requires connecting an OBD II scanner to your vehicle to read the check engine light code associated with it. For example, an error code in the P0300 range indicates an engine misfire.
Now that you know what a flashing or solid check engine light means, let’s discover the problems that trigger a flashing one.
What Causes a Flashing Check Engine Light?
Here are the issues that are likely to light up your dash:
1. Engine Misfire
The engine requires the correct ratio of oxygen and fuel for proper combustion and fuel efficiency. When something throws off the ratio, it causes improper combustion or misfire in an engine cylinder. This happens due to:
- Ignition system issues: Bad spark plugs, spark plug wires, and a damaged ignition coil prevent the air-fuel mixture from igniting properly.
- Fuel delivery system problems: Insufficient fuel reaches the combustion chamber due to a clogged fuel filter, fuel injector, or damaged fuel pump.
- Mechanical failures: Vacuum leaks and emission system issues throw the air-fuel mixture out of balance.
2. Catalytic Converter Issues
The catalytic converter converts harmful emissions, like carbon monoxide and nitrogen oxide, into carbon dioxide.
However, several issues may cause it to go bad, resulting in reduced engine performance and an increase in harmful emissions. These include:
- Burning oil in the engine
- Unburned fuel
- Oil in the exhaust
- Antifreeze in the exhaust
- Damage from impact
- Poor installation
3. Oxygen Sensor Problems
The oxygen sensor (O2 sensor) monitors oxygen levels in the exhaust system and relays the data to the powertrain control module (PCM). The PCM uses the data to adjust your engine’s air-fuel mixture.
However, the O2 sensor may fail due to aging, contaminants in the exhaust system, and faulty wiring. If there’s a faulty oxygen sensor, the PCM won’t be able to maintain fuel efficiency. In addition to the reduced fuel economy, you may also experience an engine misfire.
Bottomline: The problems listed above require immediate attention to avoid a costly engine repair.
If you plan to ignore it and continue driving, it isn’t a good idea.
Read on to find out why.
Can You Drive with a Flashing Check Engine Light?
You shouldn’t drive with your check engine light flashing as problems like engine misfires can interfere with your vehicle’s performance and put you in danger.
Driving with an underlying issue may also escalate into a significant engine problem or cause further damage to other vehicle components, leading to an expensive car repair.
Unsure about the next step to take?
Find the answer below.
What to Do When the Check Engine Light Starts Flashing
When you notice your engine light flashing, stop driving immediately and follow these steps:
- Pull over to a safe spot.
- Check your gas cap to ensure it’s tightly secured and in working condition.
- Look under the hood for any damaged components or disconnected wiring.
- Inspect for other issues like smoke from the exhaust or engine.
- Contact a mechanic. They’ll have the tools and expertise for the check engine light diagnosis and repair.
In case you’ve managed to fix the underlying issue yourself and want to reset the flashing engine light, we’ve got you covered.
How to Reset a Flashing Check Engine Light: 3 Ways to Do It
WARNING: Resetting the CEL without fixing the underlying issue could worsen the problem. But if you’ve addressed the root cause, here’s how to reset the light safely:
- Use an OBD II scanner: Connect the scanner to the port under the dash, engage the ignition without starting the car, and follow the scanner reset instructions.
- Disconnect the battery: Ensure the ignition is off and disconnect the negative battery terminal for around 15 seconds. Then, reconnect the battery.
- Drive the vehicle: If you have resolved the problem, driving your vehicle 50 to 100 miles should allow the diagnostic system to reset, which automatically turns off the light.
Wondering how much a permanent fix costs?
Check out the breakdown below.
How Much Does Fixing a Flashing Check Engine Light Cost?
The expenses for fixing a blinking check engine light vary depending on the auto repair. Here are some replacement estimates to consider:
- Damaged gas cap: $5 to $160
- Vacuum leaks: $10 to $1250
- Spark plugs: $50 to $750
- Ignition coil: $85 to $470
- Spark plug wires: $220 to $610
- Oxygen sensors: $360 to $530
- Catalytic converter: $450 to $4200
With the high costs involved in the check engine light diagnosis and subsequent car repair, you probably want to avoid unnecessary damage. There are several things you can do to maintain the components that trigger this warning light.
How to Prevent Problems Associated with a Flashing Check Engine Light
Here are some auto maintenance tips to keep that illuminated check engine light away:
- Use spark plugs recommended by your vehicle’s owner’s manual, clean the electrodes regularly, and ensure there’s sufficient spark plug gap.
- Inspect your fuel filters and clean each fuel injector every 45,000 to 100,000 miles to prevent clogging.
- Change your oil frequently, and replace clogged air filters as recommended.
- Avoid long trips at slow speeds and keep your gas tank at least a quarter full at all times.
- To prevent a faulty oxygen sensor, use high-quality gasoline and add fuel system cleaning additives every 3000 miles.
Resolve Your Flashing Light with AutoNation Mobile Service
A blinking check engine light points to a critical issue that’s compromising your vehicle’s functioning and can put you in danger. It’ll typically lead to reduced fuel economy, engine cylinder misfire, and a costly engine repair.
So, avoid driving until you resolve the issue.
If you can’t get your compromised vehicle to the mechanic, AutoNation Mobile Service will address your blinking engine light from your driveway!
We’re available seven days a week and provide a 12-month,12,000-mile warranty on all repairs.
Contact us for all your warning light issues, auto repair needs, and auto maintenance procedures.