You drive your car, and suddenly from nowhere, your check engine light starts flashing on your dashboard.
What to do now? Will my car get damaged if I keep driving it? How much will it cost? There could be a lot of questions that may be running through your head.
Luckily, we will cover everything you have to know about a flashing or blinking check engine light in this article. Let’s begin!
What does a flashing check engine light mean?
A Flashing or Blinking Check Engine Light means that your car engine suffers from a severe issue just at the moment, as long as the light is blinking. This usually happens due to occurring misfires.
The engine control unit does always constantly monitor all sensors in your car while you are driving. With this information, it calculates how much fuel should be injected into the engine and at which angle it should fire the ignition.
If one of the values from a sensor is faulty for a short amount of time, it will trigger a trouble code. If the engine control unit is getting the wrong value from the sensor several times, the check engine light will appear on your dashboard.
If this problem is severe from a misfire, it will start to flash the check engine light instead. This is to notify you that a problem that may damage the catalytic converter is happening right now.
A blinking or flashing check engine light is always caused by misfires. However, it is not as simple as that because many different things can cause misfires.
Here is a list of things that can cause a misfire, which may result in a blinking check engine light:
- Misfires on one or several cylinders (most common)
- Faulty spark plugs/Coils
- Faulty engine sensors (coolant, air temperature, exhaust temperature sensor, etc.)
- Faulty EGR valve
- Faulty/bad injectors
- Faulty crankshaft/camshaft sensor
- Exhaust emission problems
- Boost/overcharging problems
- Internal engine problem (rare)
- EVAP trouble codes
- A faulty engine control unit (rare)
How to Diagnose a flashing check engine light?
So now, when we know what could cause a blinking or flashing check engine light, where should we begin to pinpoint the problem?
You must understand that every time your check engine light is constantly lightened up or blinking, it will store a trouble code in the memory so you will have a chance to see what was causing the problem.
Therefore it is a terrible practice just to guess which parts could cause the flashing check engine light and start to replace parts. This will, in almost all cases, just make you waste your money.
A much better and more efficient method is to check what the engine control unit is trying to tell us. This can be done with a diagnostic scanner.
You may think that a diagnostic scanner is too expensive for this small problem, and in that case, you can borrow one from a friend or just take your car to a repair shop and let them read the codes for you.
After you have received the engine control unit’s codes, you will most likely find a trouble code related to a misfire. Check for more related trouble codes to continue the troubleshooting on that trouble code.
For example, if you get a misfire trouble code and one related to an ignition coil, you should definitely continue the troubleshooting on that ignition coil.
If you get misfires on a specific cylinder – check the spark plugs, ignition coils, and wirings. If you get misfires on several cylinders, there is most likely an issue with a too lean or too rich mixture.
Flashing Check Engine Light FAQ
It’s never recommended to drive with a flashing check engine light. A constant check engine light can be okay to drive with, but a flashing engine light is most likely a more severe problem. We recommend you directly either tow or drive to the closest repair shop.
Can low oil cause check engine light flash?
Low engine oil is not causing a flashing check engine light directly. However, it can cause it indirectly. If the engine oil is so low that the oil pressure will get low, it can cause a bad timing chain timing, which may cause misfires. Misfires are, in most cases resulting in a flashing check engine light.
It is not recommended to drive at all with a flashing check engine light. You can, in most cases, drive the closest way to a repair shop. We do recommend towing it if the repair shop is located far away, though.
How do I make my check engine light stop flashing?
To make your check engine light stop flashing, you need to fix the problem cause it. To make it stop, you most often have to replace the spark plug or ignition coil causing the problem. It can also be caused by a too lean or too rich air-fuel mixture.
Hi, I’m Magnus, the owner and the writer of Mechanic Base. I have been working with cars for 10 years, specialized in diagnostics and troubleshooting. I created this blog because I was tired of finding false information on the web while looking for repair information. I hope you enjoy my content!