A blinking or flashing check engine light warns you if anything is wrong with one of the vehicle’s systems or components. A constantly flashing check engine light is a sign of a far more severe problem.
Typically, it indicates that the engine is misfiring and allowing unburned gasoline to enter the exhaust system.
This causes an increase in the temperature of the catalytic converter, which may lead to serious damage. This article explains the blinking check engine light causes and how to fix it.
What Does a Flashing Check Engine Light Mean?
A check engine light is directly linked to the vehicle’s main computer. A flashing or blinking check engine light indicates that the vehicle’s computer detects that something is wrong with the engine or other vehicle parts.
The powertrain control module (PCM) of your vehicle is responsible for monitoring all of the sensors in your automobile while you are driving and calculating the data; it determines how much gasoline should be fed into the engine and at what angle the ignition should be fired.
The PCM triggers P0008, P0009, P0010, P0011 or P0016 trouble code if something goes wrong with the oxygen sensor for a brief period of time. When the PCM receives the incorrect value from an engine sensor, it turns on the check engine light.
If your vehicle’s check engine light begins to blink, you should stop immediately, turn off the engine, and fix the ongoing issue.
Causes of a Flashing or Blinking Check Engine Light
Various reasons might cause a check engine light to blink or flash. The most frequent causes of check engine light flashing are as follows:
- Low Coolant Level
- Bad MAP Sensor
- Bad PCM
- Faulty Catalytic Converter
- Faulty Charging System
- Faulty Oxygen Sensor
- Bad Mass Air Flow Sensor
- Worn or Damaged Spark Plug
- Engine Misfiring
- Engine Overheating
- Bad EGR Valve
- Bad Fuel Injector
- Bad EGR Sensor
- Bad Crankshaft Position Sensor
- Bad Camshaft Position Sensor
- Low Transmission Fluid
- Low Engine Oil
1) Insufficient Coolant Level
The low coolant level is one of the most common causes of check engine light flashing. When your car’s coolant level gets down than a specific level, the light starts illuminating and hence displays a warning of low coolant level in your car.
In such a situation, you need to refill the coolant. So, if the light is frequently glowing, it is a clear symptom that your car’s coolant is leaking, and you must figure out the problem.
Read More: Coolant Leak Symptoms and Causes
2) Bad MAP Sensor
The performance of all the vehicle’s sensors is continually monitored by the vehicle’s powertrain control module (PCM) while you drive. As the MAP sensor goes bad, the PCM turns on the check engine light to alert the driver.
Read More: Bad MAP Sensor Symptoms and Causes
3) Bad PCM
The illuminating check engine light may also indicate an issue with your vehicle’s PCM. When your PCM doesn’t properly read the information of the engine sensors, it may trigger the check engine light. Just keep in mind that the problem may be more likely with the sensor, wiring, or just about anything else.
Read More: Bad PCM Symptoms and Causes
4) Faulty Catalytic Converter
The exhaust system in your automobile has a catalytic converter, which reduces emissions. It transforms carbon monoxide and other noxious fumes into less harmful by-products.
The latest cars also have oxygen sensors. These sensors observe the efficiency of catalytic converters by inspecting the exhaust gas level.
As the oxygen sensor observes that the exhaust gas is not being properly catalyzed, it sends a signal to the PCM, and your vehicle PCM turns on the light to alert the driver.
Read More: Bad Catalytic Converter Symptoms and Causes
5) Faulty Charging System
The battery might not be the only thing that’s wrong with your car. It could also have an alternator or some other electrical component failing to charge properly, which will result in a dead engine!
Make sure you keep an eye on this area so that the charging system isn’t affected by any issues.
6) Faulty Oxygen Sensor
The oxygen sensor is a component that gets its readings from the levels of oxygen in the engine’s exhaust. If there are low levels of oxygen, then your car check engine light will start blinking.
There are many other reasons why this can happen, one of which is problems with the O2 sensor itself. If you notice a check engine light flashing on your dashboard, make sure to get it checked out by a professional.
7) Bad MAF Sensor
The mass air flow (MAF) sensor measures the air coming into your engine. This is to make sure there is enough air for fuel. Without enough air, your car will not start, or it might stall.
When the MAF sensor stops working, your PCM detects this issue immediately and leads the check engine light to come on.
Read More: Bad MAF Sensor Causes and Symptoms
8) Worn or Damaged Spark Plug
Your car’s check engine light may start flashing when there is something wrong with the spark plug.
That usually happens when you’ve got a failing spark plug slathered in oil or running too hot, causing issues with the engine operation.
However, the check engine light can also activate if there are issues with your spark plug wire, coil pack, catalytic converter, etc.
9) Engine Misfiring
As the powertrain control module (PCM) detects engine misfiring issues, it sends a signal to the check engine light, which starts illuminating and also stores the trouble code in the cylinder with the engine misfire. Use the diagnostic scanner to check the trouble code.
10) Engine Overheating
Each car has a warning light or temperature gauge that comes on to tell the temperature of the engine. If the warning light comes on, it means that the engine operating temperature is more than the normal operating temperature.
If the temperature gauge is over the red or near the top, that is a sign of engine overheating. The only issue with these devices is that sometimes they don’t work right because of a coolant leak which causes the sensor to have nothing to read.
Read More: Engine Overheating Causes and Symptoms
11) Bad EGR Valve
The check engine light may also illuminate due to a faulty EGR valve. When any part of the EGR system goes bad, the vehicle’s powertrain control module (PCM) detects the issue and triggers the check engine light to alert the driver about the issue.
12) Bad Fuel Injector
The illumination of the check engine light is one of the major signs of a bad fuel injector. Whenever the injector delivers less (and in some cases more) fuel than requirements, the engine performance reduces, and ECU turns on the check engine light.
13) Bad EGR Sensor
The EGR system has multiple sensors. The EGR position sensor is used to monitor the motion and position of the EGR pintle. The EGR pressure sensor measures the flow of exhaust gases through the EGR passages.
When an EGR system goes bad, your vehicle PCM monitors the issues and the check engine light starts blinking on the vehicle dashboard.
14) Bad Crankshaft Position Sensor
The crank sensor monitors the performance of the crankshaft and sends this data to the PCM. When the PCM monitors an issue with the signal coming from the crankshaft sensor, it triggers the check engine light to inform the driver about the issue.
Read More: Bad Crankshaft Position Sensor Symptoms and Causes
15) Bad Camshaft Position Sensor
Whenever your camshaft doesn’t work efficiently, the camshaft sensor sends a signal to the PCM, which turns on the check engine light to alert the driver.
16) Transmission Fluid
When the transmission fluid level becomes less than a specific level, your PCM turns on the check engine light.
Read More: Signs of bad Fuel Pressure Regulator
How to Diagnose a flashing check engine light?
Dealing with the cause of the issue is the most effective technique to get the check engine light to go off. If you take your car to a technician, he or she will be able to reset the diagnostic sensor on the car, which will result in the engine check light being turned off.
You can disconnect and re-connect the automobile battery if you wish to do it manually. One drawback of doing so is that all of the data held on the vehicle’s computer will be lost.
You have to be aware of the fact that if your check engine light is on for an extended period of time or blinks rapidly, the computer will record a trouble code in the memory. This will allow you to determine what was causing the issue.
The technique of guessing which components could be causing the check engine light and then replacing them is terrible. Almost often, doing this will result in money wasted.
The best and most efficient method is to look at what the engine control unit is attempting to communicate to us. A diagnostic scanner may be used to do this.
For example, if you receive a misfire error code as well as one relating to an ignition coil, you should certainly continue investigating that ignition coil.
If you are getting misfires on a particular cylinder, you should inspect the plugs, ignition coils, and wirings. If numerous cylinders are misfiring, it is most likely due to a mixture that is either too lean or too rich.
How to reset a Check Engine Light?
- Turn off the vehicle engine. Wait for a few minutes and then restart the engine. This method may turn off the illuminated check engine light.
- Reset the check engine light by using an OBD-II scanner.
- Check the coolant level and add more if needed
- Replace the faulty spark plugs
- Replace or repair the faulty fuel injectors
- Fix the issues related to the EVAP system
- Fix the engine misfiring issues
- Fix the engine stalling or idling issues
- Fix the overcharging issues
- Repair the possible vacuum and exhaust leaks
- Replace the faulty alternator
- Replace the bad ignition coils
- Replace the faulty camshaft position sensor
- Replace the faulty crankshaft position sensor
- Repair the damaged wiring
- Inspect the transmission fluid and add more if needed
- Fix the engine oil leaks and add more oil
- Fix the overheating issues
- Replace the bad EGR valve or EGR sensor
- Replace the faulty coolant temperature sensor
- Replace the bad MAP sensor or MAF sensor
- Fix the issues related to your PCM/ECM
How much does it cost to fix a flashing check engine light?
The repair or fixing cost of a flashing check engine light varies according to the vehicle model and the nature of the problem.
- Most commonly, the check engine light blinks due to engine overheating. The engine overheating fixing cost is between $70 to $1,700.
- The crankshaft position sensor replacement cost is between $160 and $230.
- The fuel injector replacement cost is from $340 to $860.
- Spark Plug replacement cost is between $15 to $130.
FAQ Section
Can I drive my car with an illuminated check engine light?
It is generally recommended that you should not drive your vehicle if the check engine warning light is flashing. It’s a true emergency. It is usually an indication that the engine is misfiring. If you continue to drive, you will certainly do irreparable harm, mostly to the catalytic converter.
How long can I drive with a blinking check engine light?
The check engine light is often a yellow or red engine shaped indicator located in the center of the dashboard, behind the driving wheel. Depending on what caused the check engine light to flash, you may be able to drive for an indefinite period of time or just for a few days. Covering between 50 and 100 miles provides the engine’s computer system time to re-adjust some of its sensors, which may fix the issue.
Is it safe to drive with a flashing check engine light?
An engine light that is blinking is quite concerning. The vehicle owner should quickly bring their car to a repair center in these situations. Taking the car there on their own may be risky for them.
What does it mean when your check engine light blinks 10 times?
The I/M readiness test, as it is commonly called, indicates that one or more emissions systems are not prepared. All of the systems will be evaluated while you drive, and the light should cease flashing after a few cycles.
What does it mean if your check engine light is blinking and then stops?
Check engine light flashing frequently signifies a cylinder misfire. In order to avoid further damage to the catalytic converter and thus higher repair costs, it is critical that any misfiring be checked and corrected as soon as possible.
Can driving with misfire damage my engine?
Having faulty spark plugs or an air/fuel ratio imbalance might lead to an engine misfire. It’s dangerous to drive with a misfire in your engine, and it might even cause damage.
Why is my check engine light blinking?
- An issue with the EVAP system
- Internal engine problem (rare)
- Misfires
- Boost/overcharging problems
- Exhaust leaks
- Vacuum leaks
- Faulty spark plugs
- Bad fuel injectors
- Faulty camshaft sensor
- Faulty EGR valve
- Faulty coolant sensor or O2 sensor
- Low engine oil
- Engine misfiring
- Engine overheating
- A bad crankshaft position sensor
- Transmission fluid leak
- Insufficient coolant level
- An issue with the radiator
What does it mean “check engine light flashing” but no codes?
Usually, when the check engine light blinks, a misfire occurs. To set a code, you need a certain amount of misfires in a drive cycle.