When your check engine light is flashing, it’s not something you should ignore. A flashing light is very different from a solid one. It usually signals a serious engine problem that needs immediate attention.
In this guide, I’ll explain what it means, the most common causes, and how to fix check engine light flashing issues step by step.
What Does a Flashing Check Engine Light Mean?
A flashing check engine light usually indicates an engine misfire. This means fuel is not burning properly inside the combustion chamber.
When this happens:
Unburned fuel enters the exhaust system
The catalytic converter can overheat
Expensive damage may occur
This is why mechanics always say:
Do not drive when the check engine light is flashing.
Blinking vs. Solid Check Engine Light
Understanding the difference is important.
Blinking / Flashing Check Engine Light
A blinking light means immediate attention is required.
Common causes include:
Ignition coil failure (may be cylinder 1 only)
Fuel injector problems ( Basically, clogging either the tripping fuel )
Fuel pump low pressure ( The Pump does not provide sufficient pressure forward to the fuel injector)
Severe engine misfire ( Multiple cylinder misfire)
If your check engine light is flashing and your car is shaking at the same time, stop driving immediately.
Solid Check Engine Light On
If the check engine light is on but not blinking:
It may be a non-urgent issue
The car may still drive normally
You should scan the vehicle with an OBD tool
It’s still important, but not as critical as a flashing light.
What Is the Most Common Cause of a Flashing Check Engine Light?
The most common cause is engine misfire.
A misfire happens when:
Spark is weak or missing ( sometime spark plug was cracked)
Too much or too little fuel enters the cylinder
The air-fuel mixture is incorrect ( Standard ratio 14.7:1)
If your car is shaking and jerking, you may ask:
Why is my car engine light blinking and shaking?
Most likely, one cylinder is not firing properly.
Common Causes of a Blinking Check Engine Light
1. Engine Misfire
Incomplete combustion affects engine performance. The car may jerk, lose power, or vibrate. Sometimes, 80km/hr jerk the vehicle.
2. Ignition Coil Failure
Ignition coils provide power to the spark plugs.
If a coil fails:
One cylinder stops firing
Raw fuel enters the exhaust
The car shakes (Sometimes, sudden acceleration time jerk feel)
This is very common in Nissan, Toyota, and many modern vehicles.
3. Faulty Spark Plugs or Wires
Spark plugs wear out over time. If not replaced:
The tip may crack
Spark becomes weak
Misfire begins
Older vehicles may also have bad spark plug wires.
4. Fuel Injector Problems
A leaking or stuck injector can cause:
Rough starting ( may require long cranking)
Jerking
Excess fuel entering the cylinder
This can trigger a flashing check engine light when starting the car.
5. Catalytic Converter Issues
If the catalytic converter becomes blocked:
Exhaust gases cannot flow properly
Engine performance drops
Misfire may occur
Ignoring a flashing light can permanently damage the catalytic converter.
Why Is My Check Engine Light Flashing Then Stops?
Sometimes the light flashes and then turns off.
This usually means:
The misfire is intermittent
It happens when the engine temperature increases
A sensor detects a temporary fault
Even if it stops, you should still scan the car.
Check Engine Light Blinking But Not Overheating
Many drivers ask:
Check engine light blinking but not overheating — is it safe?
Yes, the engine may not overheat, but a misfire can still damage:
Catalytic converter
Oxygen sensors or Air-Fuel ratio sensor
Engine components
Overheating is not required for serious damage to occur.
Check Engine Light Blinking But No Codes
If you scan and see no codes:
The issue may be temporary
Scanner may not detect pending codes
The battery was recently disconnected
Try rescanning with a professional diagnostic tool.
Check Engine Light Flashing When Key Is On Position
If the light flashes only when the key is turned on:
It may be a system self-test
Or a wiring issue in the dashboard
Possible ECU communication problem
If it continues while driving, get it checked.
Flashing Check Engine Light When Starting Car
If the flashing happens only during startup:
Weak ignition coil
Cold start misfire
Fuel delivery delay
If it stops after warm-up, still scan the car to confirm.
What to Do If Your Check Engine Light Is Flashing
Follow these steps immediately.
Step 1: Safely Pull Over
If the light starts flashing while driving:
Reduce speed
Pull over safely
Turn off the engine
Wait 2–3 minutes before restarting.
Step 2: Avoid Hard Acceleration
Do not press the accelerator hard.
Driving aggressively can worsen engine damage.
Step 3: Get a Diagnostic Scan
Visit a nearby repair shop and connect an OBD scanner.
Check for:
Misfire codes (P0300–P0308)
Fuel system errors
Ignition faults
Step 4: Visit a Mechanic
Professional diagnosis ensures:
Proper coil testing
Injector inspection ( if required, clean it)
Compression check
Flashing Check Engine Light : Diagram
Can I Drive My Car With the Check Engine Light Flashing?
No.
Driving with a flashing light can:
Damage the catalytic converter
Cause engine failure
Leave you stranded
If you must move the car, drive slowly and only for a short distance.
How to Fix Check Engine Light Flashing
The solution depends on the root cause.
Most common repairs:
Replace the ignition coil
Replace spark plugs
Clean the throttle body and programming or learning
Repair the fuel injector
Fix wiring issues
Proper diagnosis is essential before replacing parts.
Frequently Asked Questions
Q) Why Is My Check Engine Light Flashing Then Stops?
It may be an intermittent misfire. Scan the vehicle to confirm.
Q) Why Is My Car Engine Light Blinking and Shaking?
This usually indicates a cylinder misfire caused by ignition or fuel issues.
Q) How Do I Stop My Check Engine Light From Flashing?
You must fix the underlying issue. Clearing codes without repair will not solve the problem.
Q) Can I Drive My Car With the Check Engine Light Flashing?
No. It can cause serious engine damage and expensive repairs.
