flashing check engine light

Flashing Check Engine Light Causes & Solutions

In Engine by Magnus Sellén20 Comments

flashing check engine light

You are driving your car, and suddenly from nowhere, your check engine light is flashing on your dashboard.

What to do now? Will my car get damaged if I keep driving it?, How much will it cost? There are a lot of questions that are flowing through your brain. But don’t worry.

I work as a car diagnostic technician, and in this article, I will learn you what the check engine light is and how to fix it the fastest and cheapest way.

What does a Flashing Check engine light mean?

When the engine light is flashing, it means that there is a problem with the engine and there is a trouble code stored in your engine control module. Most often the engine light is not flashing, but when the engine light is flashing, it means that the problem with the engine occurs right now at the moment and it’s a more serious problem like a misfire.

The Engine control unit is all the time receiving values from all the sensors of the car engine. When it gets all the information, it calculated how much fuel it should inject 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 all the time, the check engine light will be flashing until it gets the correct value again.

Common Causes of a flashing or blinking check engine light

The check engine light is most likely to blink if it’s a severe constant problem, like an occurring ignition misfire, injector or a temperature sensor problem, that have an essential part of the engines running. In rare cases, there could also be an internal engine problem or a faulty engine control unit. From experience, a flashing check engine light is most often a misfire, EGR or an exhaust temperature sensor.

  • 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
  • Faulty Engine control unit (Rare)

Is it safe to drive with the check engine light flashing?

It’s never recommended to drive with a flashing check engine light. A constant check engine light can be okay to drive with sometimes, but flashing engine light is most likely a more serious problem that has to be fixed as soon as possible.

If you notice the check engine light flashing when you are out and driving, you should drive the shortest way to a mechanic workshop to let them take a look before you keep driving. Driving with a flashing engine light can result in more expensive problems with your engine.

One example is if the car is misfiring/not running at all on one cylinder, and you keep driving for a long distance, you can either fill up the catalytic converter with fuel and destroy it. Because the fuel on that cylinder won’t get ignited, the fuel can run down through the piston rings into your oil pan, and it can result in a whole new engine if unlucky.

My recommendation: Do not run your car with a flashing check engine light, tow it to the closest workshop if possible.


How to find the problem with my flashing check engine light?

nexpeak t501 obd2 scanner

The first thing you should do if the check engine light is flashing or is constant on your dashboard is to read the trouble code memory. When the engine light is showing up, and the engine control unit recognizes a problem with the engine, the engine control unit will store a trouble code in the memory. The code will be stored there for a long time, so you have the chance to read the trouble codes. But remember that the engine control unit can erase the code itself after a while if it finds the problem fixed, so don’t wait for too long to read the codes.

To read the trouble codes from the engine control unit, you need an OBD2 scanner. You can either drive your car to a workshop and let a mechanic read the trouble codes from the engine control unit. You can also do it yourself if you have a scanner. If you do not have a scanner but are interested in getting one, I can recommend the NexPeak T501 that you see in the picture. You have a lot more functions than reading the trouble codes with it, and you can do the most advanced troubleshooting on your engine with it.

You can check the price of the Nexpeak scanner if you click on the button down below. The link is to Amazon.com
Check Price on Amazon


  • A flashing check engine light means that the problem occurs at the moment and it’s most likely a more serious problem like a misfire.
  • It’s not recommended to drive with the check engine light flashing or ON.
  • The problem is most likely a misfire, combustion or a faulty engine sensor problem
  • When the problem occurs, the best way is to check the trouble codes with an OBD2 scanner. You can do it yourself at home with a scanner.

If you have any other questions about a flashing check engine light or want to share your story of how you fixed it, comment down below. If you have any other car questions, you are welcome to ask them at our homepage.

Hello I'm Magnus, the owner and the writer of this website. I have been working with cars since I was 16 and I'm specialized with in-depth Automotive diagnostics. Also been driving drifting for the last 6 years. I'm here to give you answers to all your automotive questions and I hope that you enjoy our content.

  1. Friends,
    I have a 2005 Subaru legacy SOHC 2.5L engine that went bad. I was told by the store selling me an engine that I could put a 2.0 SOHC in and it would fit and work perfect. I replaced the motor and the 2.0 fit perfectly! Now the bad. However my check engine light is flashing! I took it to my auto pros (a different shop) and they put a factory obd machine on it and said they were stumped as there are NO OBD codes! They said the car runs fine as they checked it out. However no OBD Codes. A BIG, HELLLP! Any feedback Master of the Mechani internet Universe?

    1. Author

      Either the instrument is not working together with the engine control unit if you replaced it, or there are stored trouble codes but the code scanner could not read these.

      I would recommend using a Subaru code reader if possible. Some scanners can’t read manufacturer codes! 🙂

      1. Did spark plugs affect Engine flashlight for Opel corsa hatchback?

  2. Hi
    In our country the rain made lakes in all our roads so i drived in some water lakes on certain road and the water was minimum 50cm high and it entered my car honda accord model 1988 and when i reached my home it suddenly turned off and would turned on again because the check engine is blinking and there is other devices next to the engine are blinking noise sound. So what shall i do?

    1. Author

      You should absolutely read the trouble codes with a scanner and see what it says. Most likely you can erase the codes and keep driving as there was maybe bad connection in the wirings caused by the water.

  3. My engine light was on my 4 cylinder 2001 Honda CRV. I took it to Goodyear and they scanned at and said there were misfires on cylinders 2, 3 and 4. The car was driving fine though (4 hour drive on the way to the shop). They replaced spark plugs and wiring and then the engine light began flashing. They scanned it again and it’s saying there’s random misfiring now. I had to drive it home from Charlotte, NC to Atlanta, GA and now problems with the car or engine temp… Any recommendations on what to do next?

    1. Author

      @Amy C
      Random misfires are often caused by a faulty fuel mixture. Common things for a lean mixture is an intake leak/PCV valve problems. It can also be caused by low fuel pressure in the pressure rail. However, I would begin with checking for intake leaks and make sure that the PCV valve is in good condition.

  4. I have an 02 Dodge Durango 4.7 L , it has recently popped a code PO302. Cyclinder 2 misfire. I have replaced the ignition coil module on cyclinder 2 & the throttle position sensor. However, after 3 – 4 days of driving it reappears again. What else could it be?

    1. Author

      @Van Did you check the spark plugs on the affected cylinder? It could also be a wiring problem or a faulty injector (not very common though). I would check and replace the spark plug if you haven’t!

  5. I have an old Chevy 2008 impala that I use to tow an18 ft boat and use it only for that. The engine light has come on and it has been that way for months. Scanner shows code po172. Once in awhile light goes off for a day then comes back on. Now that it is warmer the engine light does not come on for the past week and I have been using it a lot around town for errands. The engine code is still showing up on the scanner and I have not erased it. The engine light comes on when I start the car and then goes off. Afraid to get stuck somewhere with the boat so I think I am going to put a hitch on both or one of the Rav 4’s. Do you think I should still use the Chevy if the light comes on again.

  6. 05 trailblazer a code came up po300 misfiring ok I change two coil packs n all 6 spark plugs .started it up n still running rough no codes came up like before but when you floor it check engine flashes let off gas it stops n goes off.n it smells bad when running could it be my catalytic converter stopped up causing it to do that

  7. My 99 beetle sounded like the battery was dead I replaced the battery the starter and alternator are good the battery lite blinks and my car sound like the battery dyi g what is wrong with it susan

  8. I have Kia Opirus V6 2700 cc the check light starts blinking and when switch the engine off and restart again the car drives smooth and the blinking disappears and reappears again after a while with lose of engine power . On checking with scanner I was informed that miss fire was diagnosed in almost all engine units and I was advised to replace all spark plugs which I did. The car drove few miles and same symptoms reappeared with check light flashing and loss of power, Injectors seem to be OK as I was told by the mechanic . I would be thankfull if you would shed some light on what could be the problem.

  9. Good day my car is not starting i took a wire from the fan to the egnitio and the wire touched the cars boddy while the egnition was on and it made a short now my engin light is blinking the engin turns but does not start. Opel corsa 1.4 itsa 2006model

  10. I drive a Toyota Camry 2010 LE, 2.5 ltr. Check engine sing appeared. Machine read: Cylinder no. 1 misfires. Sometimes it starts flashing. When it flashes, the car doesn’t picks up instead of accelerating. But it becomes static gradually by releasing the accelerator. Or by stopping at the signal light point. Mechanic first changed 4 plugs. It did not resolve the problem. Then he changed the coil. But problem did not go. Now I am taking the car to the Toyota Dealer’s service station. I am afraid how much they will bill me. Although initially I am going to take it for diagnosis purpose.

  11. Good day, My name is Ibrahim, I was coming from office yesterday and I discovered my check engine was blinking , I need your advice on what to do.

  12. 2010 Honda Crosstour with 82,000 miles. Twice at 65-70 mph the check engine light flashes. Car drives fine. Dealership has checked for codes and there are not any. Sparkplugs were replaced at 70,000. Any ideas? Dealership recommends drive it until they can catch the check engine light blinking.

  13. I drove a brand new dodge van, when I parked it, I turned off the van but left key on to listen to the radio, in less than a minute engine light began to blink, then it stood on constant. I turned key all the way to the left, and turned van back on and engine light was gone. Can the key turned to the right caused the engine light to blink?

  14. I have an 06 Nissan Altima 4 cylinder, the check engine light came on while driving and it was blinking but when I pulled over and turned the car off and retsarted it the check engine light was off. A week went by and then while driving the car shut off and would not start. Any ideas of what it could be? I’ve never had spark plugs replaced or had the timing replaced.

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