Check Engine Light Flashing When Key Is on Position: Fixes

Check engine light flashing when key is on position can be disturbing, especially when you don’t know the causes. Every car has a system of dashboard lights that show various car-related information. Depending on how long it flashes, this particular light might mean multiple things, which can be perplexing.

Check Engine Light Flashing When Key Is On Position

This article will explain why your check engine light is flashing and the possible solutions you can try to fix it.

Why Does Your Check Engine Light Flash When the Key Is in Position?

Your check engine light flashes when the key is in position because of a loose fuel cap, faulty catalytic converter, or faulty air flow sensor. Sometimes, it can be due to faulty spark plugs, faulty oxygen sensors, or your engine still needs to warm up.

– Unstable Fuel Cap

When this light illuminates, there are rarely any major engine problems, especially if the engine has not even started. The gasoline cap is typically where the issue is located. Before hiring a mechanic, if you ever experience this problem, check the gas cap first.

Other more sensitive auto parts will take a beating if this relatively unimportant auto part becomes loose or breaks. This will activate dashboard-reflecting automobile sensors. One of these delicate auto components is the emission control sensor, which may think there is a gasoline leak because of the excess air in the gas tank. Tighten the gasoline cap immediately, then wait a few minutes before checking for improvement.

– Damaged Catalytic Converter

The engine light may flash as a result of a damaged catalytic converter. This should be evident because employing a subpar catalytic converter can seriously harm engines. If you decide to continue driving the automobile despite the flashing light, other symptoms will emerge. Any attempt to accelerate quickly will be rebuffed as the car becomes sluggish and the exhaust smoke darkens.

Causes of Check Engine Light Flashing When Key Is On Position

Replacement is the only option for a damaged converter, and we must admit that it is anything but inexpensive. However, the price varies based on the vehicle type and the shop’s going rate.

– Terrible Air Flow Sensor

Fuel and air are the two sources of energy for the car. Lights will likely flash if either delivery is delayed or stopped. The airflow sensor is the most vulnerable part and is readily breakable if not constantly examined. The engine light will illuminate, but this is not cause for concern.

The automobile will start and move off, but other features, such as fuel efficiency, will suffer. However, you can avoid the hassle by replacing the airflow sensor at any authorized repair facility. The process is swift and reasonably priced. Make sure to have the flow sensor checked when you next go to the mechanic.

– Faulty Spark Plugs

Since modern cars’ spark plugs are designed to last almost as long as the vehicle, this is uncommon. However, high-mileage models are less fortunate. Their spark plugs can fail at any time during the vehicle’s life. Before you blame the spark plugs, eliminating other conditions is a good idea because the symptoms of bad plugs can occasionally resemble those of other auto issues.

Well, spark plugs in many cars may be simply switched out. However, this is only for experienced drivers. We advise that new vehicle owners have a mechanic handle it. This will ensure that your car is in safe hands and the switching out is done accurately.

– Damaged Oxygen Sensor

The oxygen sensor functions more like an airflow sensor, except that it tracks how much oxygen is expelled through the exhaust. Although driving with a damaged O2 sensor won’t ground your car, it could easily harm the converter. As we already mentioned, this is pretty expensive to repair.

Damaged Car Oxygen Sensor

Poor fuel economy is another quick and direct effect of driving with a damaged O2 sensor, so you may need to change the sensor. You can change the sensor at any point in time for lower prices. But again, we recommend that you have it done by a qualified auto mechanic.

– Engine Not Warmed

If you start the car after spending a lot of time in the yard, the engine may take some time to warm up. The check light will be on as a result. You can start the automobile and take it slowly as the warm air circulates through the engine. After that, the light ought to go off; if not, you should call your mechanic immediately.

How To Fix Flashing Check Engine Light While Key Is in on Position?

To fix a flashing check engine light while the key is in the ON position, you can try performing a trouble code scan, checking the car’s ignition coils and spark plugs, examining the fuel pressure, examining the engine sensors, or seeking professional assistance.

On the other hand, starting the ignition might naturally cause the CEL to illuminate in some vehicles. This is common for cars and is a sign that your check light and all other engine-related lights are working correctly.

You should be concerned if the light doesn’t turn on since a broken light bulb will prevent you from knowing if your engine has an issue. This may also be the case if you recently purchased a used vehicle. Replacing the light’s burned-out bulb may be necessary if it suddenly stops turning on. The light will go off when the engine starts, and you won’t need a scanning tool to reset it.

However, the light might continue to be on once the engine has started running if the car’s computer detects any problems with the engine. Some solutions to address the underlying issues include the following:

– Perform a Trouble Code Scan

Begin by scanning for trouble codes to diagnose the problem behind the flashing check engine light. Use a professional code scanner to retrieve the Diagnostic Trouble Codes (DTCs) stored in the car’s computer. Various OBD-II scanners are available, each capable of reading different codes.

Solutions for Check Engine Light Flashing When Key Is On Position

Alternatively, if you do not have a scanner, consider visiting an auto parts store that offers complimentary scanning services. Once you have obtained the trouble codes, proceed with troubleshooting based on the specific codes found.

– Check the Vehicle’s Ignition Coils and Spark Plugs

If the code indicates a problem with the ignition coils, replace the faulty coils as indicated by the trouble code. Similarly, if the trouble codes suggest a fault in the ignition system, examine the spark plugs. Carbon buildup on the plugs can lead to failure, necessitating their replacement.

– Examine the Fuel Pressure

Using a specialized gauge, assess the fuel pressure and consult your service manual to determine the expected normal reading. Advanced scanners may also enable fuel pressure checks. In the event of abnormally low pressure, diagnose the faulty component and proceed with a replacement.

– Examine the Engine Sensors

While physically inspecting every engine sensor may be impractical, the code scanner can help identify the potential culprit. Once you identify the problematic sensor, attempt cleaning it thoroughly and reinstalling it. If cleaning proves ineffective, replacement becomes necessary.

– Seek Professional Assistance

Take the flashing Check Engine Light seriously, as it indicates a potentially significant issue. Therefore, it is advisable to consult with a professional in certain cases. Don’t take any chances when it comes to your car’s engine. Whether you require diagnostic assistance or repairs, invest time in finding a trustworthy and reputable repair shop.


– What Is the Effect of the Check Engine Light Not Turning On?

The effect of the check engine light not turning on when the key is turned is a damaged CEL bulb. The check light bulb will eventually burn out because it doesn’t last forever. When the key is turned on, the light won’t turn on if this occurs.

A blown fuse in the ignition switch may also be problematic, causing the ECU to malfunction and affecting the Check Engine Light. This is quite dangerous. It is not normal, and it’s not a good sign. This happens for multiple reasons, and you should check out what could be wrong if you notice this happening.

– When Is The Check Engine Light Flashing a Cause for Concern?

The check engine light flashing is a cause for concern each time the light begins to flicker while the engine is running. You should be more alarmed by a flashing or blinking CEL than a steady one because it denotes a severe issue with your engine that must be fixed. We just explained that if the engine light flash when you turn on the ignition, there is nothing to worry about, but if the CEL is flashing, we advise against trying to drive your car any further.

The possible fix if the check engine light is on after starting the engine is that you must visit the repair shop to inspect your vehicle for any hidden problems. It means your engine has problems. The illumination may be constant or intermittent.

Fortunately, the error codes that caused the check light to illuminate will have been stored in the computer’s memory. To determine the problem your engine is having, pull the codes using a code reader. Try to stop the vehicle and have a mechanic check the check light. Alternatively, you might have it hauled to the repair shop for evaluation and maintenance.

Check Engine Light Flashing When Key Is On Position Details


This article has taught you that you shouldn’t be concerned if the check engine light flashes when you switch the key without starting the engine.

Let’s have a list of some of the essential points mentioned:

  • Check engine light is flashing when the key is in position because of a bad converter, faulty air flow sensor, or bad spark plugs. It may, sometimes, be due to faulty oxygen sensors or even because your engine is not warmed up yet.
  • If your check engine light flashes while the key is in the ON position, you shouldn’t take any action. Instead, you ought to be glad that starting the ignition caused the CEL to illuminate.
  • When the check engine light is not on when the key is turned on, this is dangerous. It is not normal and it’s not a good sign.
  • The check engine light flashing is a cause for concern each time the check engine light begins to flicker while the engine is running.
  • The possible symptoms of a bad engine are dark smoke from the exhaust pipe, constant overheating, knocking noise from the engine, low fuel economy and rough idle.

The light should briefly illuminate before turning off once the engne is started. This quick and easy bulb check ensures the CEL bulb and other system lights are operational and will warn you if a problem arises while driving your car.

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