Why does the Check Engine Light Stay on After Fixing Problem

Why Does The Check Engine Light Stay on After Fixing Problem

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Being a car owner can get frustrating, especially when your check engine light stays on after fixing the problem. In this article, we cover some of the possible reasons why this is happening.

The check engine light indicates the presence of a malfunction with one of your engine system components or it could be a simple problem such as the loose gas caps.


There are multiple instruments in your vehicle designed to identify the various issues it may be facing. One of the common detectors in this category is the check-engine light. The feeling of dread that enters most people when faced with this signal indicates the importance of this particular system.

Turning it off requires you to deal with the problem it has located adequately. Sometimes the light might persist due to a number of the not obvious reasons. Some popular ones include not dealing with all the problems it has detected or not meeting the conditions for the system test. In other cases, your car might simply need a couple of warm-up cycles without incident for the light to turn off.

Should your check engine light remain on after taking your car for an initial servicing, the best response would be seeking professional help. It should be noted that the reasons for this issue are not always severe ones. However, if the light starts blinking or turns red from yellow, then the change of color is representative of a serious issue that needs attention.

Types of the check engine lights

As regards your check engine light it does offer two types of warnings one is the check engine light flashing, and if you are driving your car and by any chance you see your check engine light flashing then you know you have a big problem in your hand that needs professional assistance.

So the first thing that you should do is to stop and pull your car over to the side and have it towed to a dealer shop for diagnosis. And if the check engine light flickers on and doesn’t go away then it could be experiencing a wide range of problems some of which have been discussed below and should thus be taken to a garage.

Why a Check Engine light might persist

Due to the multiple areas monitored by the onboard diagnostics system of a vehicle, the check engine light may remain after numerous attempts to turn it off. Some of the causes behind this problem can include:

Delayed Response

In some cases, your vehicle might simply need to confirm an issue is genuinely resolved before turning the check engine light off. So if your question is does the check engine light turn off automatically after repair – then the answer is yes. However, this doesn’t always happen immediately, sometimes you might have to wait for the diagnostic system to realize the problem has been resolved.

The confirmation process is conducted automatically, but you have to take your vehicle through a couple of warm-up cycles to rush the process. This is achieved by turning your car on and off two or three times consecutively. You can also simply choose to continue driving if you’re on the move. Once the system has determined there are no more problems with your car, the light will be turned off automatically.

Additional Problems

You might not always be aware of all the problems with your engine. If you’re already dealing with a particular issue, you could automatically connect the light to that problem. This means that once you get it fixed, you will be expecting it to turn off. However, if there is another problem with the vehicle, then this will not happen.

You need to ensure that you have adequately sought out and addressed all of the complications affecting your car in such circumstances. And this you can do by using a code reader to pinpoint the specific issues identified by the diagnostic system.

Faulty Oxygen Sensors

If you’re still asking will the check engine light turn off after repair – you should also consider other parts of your vehicle. As with all mechanical creations, a weak link can affect the capabilities of your car’s overall diagnostic systems. One of the issues you should look into is the state of your oxygen sensors. These measure the unburned oxygen present in the exhaust to monitor how much fuel underwent combustion.

A faulty sensor could lead to the delivery of inaccurate information to the diagnostics system. This, in turn, can result in the check engine light remaining on as your gas mileage decreases. The malfunction can happen as a result of the accumulation of ash from the oil burned. Replacing the filter in your sensor on an annual basis is an excellent way to avoid this issue.

Spark Plug Failure

The spark plugs in your car help with sealing the combustion chamber. They also host the gap needed for a spark to jump across and commence combustion. If you’re working with faulty spark plugs, misfires can tend to take place. A good way to identify this particular problem is by noting a jolt in your vehicle during acceleration.

Replacing these items are a quick and straightforward process that can result in your check engine light switching off. In most cases, modern spark plugs can last for about 100, 000 miles before they need to be replaced. The process is easy enough to be accomplished by most drivers once they attain the required know-how.

Problems with the Catalytic Converter

The catalytic converter is responsible for reducing exhaust gases in your vehicle. It does this by converting elements such as carbon monoxide into safer compounds for the environment. A failure in this function can cause a reduction in your gas mileage. You may also find that the ability to accelerate is significantly diminished over time.

However, you should note that a failure in this sector is a rare occurrence. As long as you properly service your car on a regular basis, you shouldn’t be faced with this problem. Should this area be the reason behind your check engine light – then switching mechanics might be a good idea. It’s crucial that you address this issue as soon as you can to prevent any long-term problems with your vehicle.

You have a Faulty or Loose Gas Cap

A gas cap may not seem like a very important part of any car but believe it or not, they matter. A damaged cap can result in fuel vapors leaking out. This can have adverse results on the overall fuel system, causing a reduction in mileage.

Sometimes the lid may simply be loose and isn’t damaged at all. Replacements are available from a variety of stores and cost just a few dollars. Its installation is also not a difficult process and doesn’t necessarily require professional assistance.

In conclusion, the question will a check light reset itself will depends on the particular circumstances of your vehicle. If you are looking for a means to reset the light immediately, then implementing an OBDII scanner is a great option.

You can either buy this device for your own personal use or visit an auto shop offering such services. Addressing any problems identified by this signal as quickly as possible is also crucial to maintaining reliable operational levels within your car.

How to know the problem illuminated by the check engine light

The lighting up of your check engine is a clear indication that your car has a problem and since we want to put a finger on the problem, there is technologically able equipment that will do that specific job and that is the OBD II Scanner.

The scanner will, therefore, retrieve the trouble codes. The scanners are of different types as there are those that will provide you with codes and their meanings and there are those that will just provide you with the codes for you to interpret. An example of the codes that you will be provided with are such as letters A, B, and C, which stand for hybrid propulsion.

Letter B also indicates that there is a problem with the body and this covers the Airbag or the AC. Letter P stands for power train or rather the engine transmission or gearbox and U for user network. You might also meet with numbers beginning from 1 to 9, in which 7, 8 and 9 stand for the transmission. Number 1 is for fuel and air metering, while 3 represents the ignition fire system or misfire.

Frequently Asked Questions

  • Does the check engine light always indicate something bad?

Well, a check engine light going on can cast a very dark cloud in your head but it could be something serious or a very simple DIY problem that will go away quickly.

  • Can the low oil level cause the check engine to come on?

The most probable cause for your check engine to come on is electric and mostly related to the engine. And a low oil level has got nothing to do with your check engine level and it can never make the light come on.

  • Can the check engine light, light up with no reason?

A loose or faulty gas cap can make your check engine light to come and stay on. If the above happens then you will have to drive your car around a few times to get the diagnostics system to reset and turn the light off.

  • Can the failure to change oil make a check engine light to come on?

If you properly changed your oil then there is absolutely no reason why your check engine light should come on but if it, however, does come on then you should know that there is another problem with the car and not necessarily the oil change.